Electronics – Thomas R. Bewley, Christopher M. SCHMIDT-WETEKAM, Nicholas Morozovsky, Matt Grinberg, University of California
Abstract for “Multimodal dynamic robot systems”
A robot system consists of a frame or body that has two or more wheels, each one rotatably mounted on it. Each wheel is driven by a motor. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The signals can be generated for forward, backward, or climbing motions. The power source provides power for the drive motors, the system controller, and any or all of the sensors.
Background for “Multimodal dynamic robot systems”
Robots can be used for everything from material transport in factory environments to space exploration. Mobile robots are being widely used in the automotive industry. Robots move components from the manufacturing stations to the assembly lines. These autonomous guided vehicles (AGVs), which follow a track on a ground, are able to avoid obstacles and avoid collisions. In recent years, attention has been given to autonomous mobile robots that can be used for space exploration and sample collection, such as NASA’s Mars Exploration Rover. This has led to the advancement of mobile robotic technology and an increase in effectiveness of mobile bots in a variety of applications.
“Mobile robot technology has been largely focused on robot designs that have wheels to move. This has allowed for advancements in the planning and control of the rolling wheels. Despite these advances, wheeled mobile robots still have serious shortcomings that have yet to be addressed. Wheeled robots often have trouble traversing uneven terrain. This problem can be solved by increasing the wheel size. However, increased wheel sizes can have undesirable consequences such as an increase in overall size and weight. Additionally, increasing the size of the wheels does not always result in an increase in payload capacity or other operational features. The harsh operating environment of chemicals and heat can also negatively affect wheeled robots.
U.S. Patent Publication No. 6285 A1 describes a variation of a wheeled robotic that can address certain problems found in harsh environments. 2008/0230285A1 shares partial inventorship with this application. This application is incorporated by reference. It describes the first vehicle that combines wheeled locomotion and hopping. Multimodal robots can be used to add hopping and climbing capabilities to wheeled robots by attaching an axle to a central leg. This allows for relative movement between the axle and leg to lift the axle. You can create a hopping effect by using a sudden downward force to push the leg against the support surface. To climb the stairs, apply a steady force against a support surface. Additional stability is provided by the leg for moving across uneven terrain. One embodiment of the multimodal robot’s wheels is mounted on independently-moving parallelogram linkages that allow the wheels to change relative orientations or tilts.
The rolling robot is an alternative to the wheeled robotics. Rolling robots are those that roll on their entire outer surface, rather than external wheels or treads. They are cylindrical or spherical in shape and only one axle (if any) and an outer surface that is actively involved in the robot?s movement. All state-of-the art rolling robots work on the principle that the center of gravity of a wheel/sphere is moved. This causes the wheel/sphere to fall in the desired direction and roll along. Rolling robots offer many advantages over wheeled ones. They can travel on any surface, even water, and can move in any direction.
“Improving methods of locomotion is necessary to enable robotic systems to move in environments that are not possible for current-used robot locomotion designs. These improvements are described in the following description.
“It is a benefit of the invention to provide a multimodal robotic system that can operate efficiently on difficult terrain and/or in harsh operating conditions.”
The robotic systems of the invention are described as having a frame or body that has two or more wheels that can be mounted on it. Each wheel is driven by a motor. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The signals can be generated for forward, backward, or balancing motions. The power source provides power for the drive motors, the system controller, and any or all of the sensors.
A robotic system according to one aspect of the invention includes a frame that has two or more wheels mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source provides power for the drive motors, the system controller and any or all of the sensors. Each arm has a distal end where a wheel is mounted. A proximal and a centrally placed leg are located between the arms. The proximal ends of each arm are rotatably attached at the leg. An arm motor is mounted on each arm to drive the rotation of an arm relative to the leg. This is so that the legs are arranged vertically with one end in contact to a support surface. (i) Downward symmetrical rotation is performed by the arms to position the wheels in contact on the support surface. (iii). Rapid upward symmetrical rotation is done by the arms to lift the leg off the support surface and produce a hopping motion. (iii). Antisymmetrical rotation is used to balance the frame at the leg.
A robotic system according to another aspect of the invention includes a body having two or more wheels that can be rotatably mounted on it and a motor for driving each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward, backward, climbing, hopping and throwing. The power source provides power for the drive motors, the system controller, and any or all of the sensors. The chassis consists of two drive wheels that are rotatably mounted on opposite ends of the body. Each drive wheel is positioned on an axle which is turned by a corresponding motor to rotate the drive wheel. An elongated pair of arms are mounted perpendicularly to the chassis on the opposite sides. Each arm has a proximal and distal ends that are mounted on the same axle. A second wheel is then mounted in the same plane as the corresponding drive wheels. Each arm is linked to a second motor. A linkage between each motor and the axle for each arms causes the second engine to rotate the chassis relative to the other. The distal or proximal ends of the arms can be balanced by independent activation of each motor. A joint with two degrees of freedom can include the linkage between each arm’s second motor and its axle, as well as the linkage between each drive motor and the wheel. Each arm can support a track in one embodiment.
“A robotic system according to another aspect of the invention includes a body with two or three wheels rotatably mounted on it and a motor for driving each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source provides power for the drive motors, the system controller, and any or all of the sensors. The body consists of a chassis with two drive wheels that are attached to each other and rotatably attached to a drive motor for rotating the wheel. An elongated pair of drive arms are mounted perpendicularly to the chassis on the opposite sides. Each drive arm has a proximal end that is attached to a corresponding axle and a distal one which supports a second drive wheel in a common plane. The boom arm is composed of a weighted section attached to connector arms. These connector arms are pivotably mounted on either side of the chassis so the weighted part is parallel to the chassis. A linkage connects the connector arms to at least one motor so that activation of at least one motor rotates the boom arm relative the chassis. The at least one motor can be activated independently to shift the center of gravity, allowing for balance on either the distal or proximal ends of the drive arms. The system controller controls both the drive motors as well as the at least one motor to shift the center of gravity reactively for stability. Each arm supports a track in one embodiment.
A robotic system according to another aspect of the invention includes a frame that has two or more wheels that can be rotatably mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source for powering the system controller, drive motors and one or more sensors is also included. Two or more wheels are made up of a plurality reaction wheels. The motor that drives each reaction wheel is housed within a housing. This housing contains a plurality momentum exchange elements, which are mounted on one or several axes attached at the frame. The frame has a geometrical structure that allows multiple momentum exchange elements to be distributed around the frame in order to generate angular momentum in different directions. One variation of the axes comprises a single gimbal-axis with a corresponding motor. Another variation is to have the axes consist of a single gimbal-axis with two corresponding motors. To protect the frame and momentum exchange components, a shell can be added.
“A robotic system is also described in another aspect of the invention. It includes a body that has two or more wheels mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The system controller, drive motors and one or more sensors are all powered by a power source. The body is a cylindrical with a rotational direction, with two ends. Each end defines a hub that aligns with the rotational axle for rotatably holding a wheel. A cavity in the body contains a volume for storage of objects having a specified diameter. The body is surrounded by an elongated arms that extend perpendicularly to the rotational direction. This allows a portion of the storage volume to communicate with the base portion. The elongated arm’s lower portion is located opposite the body and runs parallel to the plane that divides the cylinder. On each side of the bisecting plan, a curved channel is found. It has an exit end that communicates with the storage volume, and an entrance end that is defined by the hub and the inner surface of the wheel. Each channel is designed to receive the object and create frictional contact between its inner surface, the hub, and the lower portion of the body. This allows the wheel to draw the object into the channel. The motors can rotate the body relative to the wheels, so the elongated arms can be oriented horizontally. The elongated arm is oriented horizontally. Rapid activation of motors causes the wheels to turn in a first direction. This causes the body to revolve around the rotational axis in the opposite direction, accelerating the horizontal arm to a vertical position. As the elongated arms accelerate toward vertical position, an object placed on the base of the elongated arms rolls towards the distal end. The object will be thrown once it reaches the end of its arm.
“In the first exemplary embodiment, enhanced mobility in harsh environments, such as rough terrain or hazards, can be provided by a modified wheeled robot that combines a hopping capability with a leaning maneuver. This inventive robot has an end-over-end stair climbing ability. It raises its center mass above the obstacle and balances the vehicle on its toes. The drive wheels then shift their mass side-to-side for balance.
“The first embodiment of the robot consists of two independently driven wheels that are mounted on the ends and two independently driven arm assemblies. These pivot around a central leg to create either symmetric or anti-symmetric rotation depending on the desired motion. The arm assemblies can be adapted to travel linearly along the length the leg using a non-backdriveable motorized led screw. This linear motion allows for the vehicle to switch between an upright roving and toe-balancing configuration.
“The independently-actuated arms can function both as a hopping mechanism when rotated symmetrically about the central leg, and as an actively-controlled roll-axis stabilizer when rotated anti-symmetrically relative to the central leg. The robot can simultaneously stabilize and hop in its roll axis plane if the motions are properly superposed.
The multimodal robot of this invention is a better design than previous designs. It can leverage a highly efficient leaning maneuver and still have the hopping abilities to jump onto a platform or cross a gap.
“Applications for the multimodal robot of the first embodiment include reconnaissance in burning or chemical-contaminated environments, monitoring hazardous materials (e.g. “Providing mobile platforms for weapons and exploration of the planets, as well as for incorporation into toys, nuclear waste stockpiles.”
A second embodiment of a multimodal robotics system combines the ability to roll, balance and climb in a vehicle with treaded wheels or treads. This is done by shifting the vehicle’s center gravity relative its chassis. The vehicle can perform and stabilize ‘wheelies? You can also use?reverse wheelsies? Also known as’stoppies? An exemplary embodiment of the robot can overcome obstacles almost as high as its length (in its folded configuration). It does this by reconfiguring its center of gravity to overcome these obstacles. To carry sensors, cameras, payloads, or other electronic devices, a platform or frame should be connected to the chassis. Motors that drive the wheels or treads can be set up to rotate independently of the chassis. This allows the wheels or treads to be used for both rolling and balancing. This allows the robot dynamically adjust its center gravity. The robot can calculate its angle relative to gravity using MEMS accelerometers or gyroscopes. The robot can stand upright on its treaded toes by unfolding the tread assemblies. The robot can stand on its treaded?toes to expand the view from an onboard camera or other sensors and overcome obstacles that would otherwise prove impossible with a treaded robotic. This design can also cross chasms almost as large as the vehicle’s length and use the pivot on the chassis to dampen vibrations while driving over rough terrain quickly. You can choose from several modes of locomotion to adapt the robot for the terrain. This multimodal robot’s unique mechanical design and feedback control algorithms allow it to conquer complex terrain (e.g. Stairs, rubble), while maintaining a compact form factor to navigate in tight spaces and to lower cost and weight.
An actuated boom can be added to an alternative configuration for easier climbing and balancing. The boom is approximately the same mass as the chassis. The robot is equipped with motors to drive the wheels or treads and adjust the angle of the boom relative to the chassis. The robot’s configuration is detected by sensors, including one or more level sensors on each axis. These signals are sent to a controller. To allow the vehicle to balance on its treaded wheels or front toes, feedback may be used. You can also use the vehicle to climb over obstacles, including stairs. To do this, extend the boom’s mass over the obstacle and rotate the chassis upward and over. The maneuver can be performed in either a statically stable or dynamically balanced fashion. The boom arm can be extended and/or configured with its own wheels, treads, or both.”
“The robot’s center gravity can be shifted to allow it to overcome obstacles almost as high as its vehicle (in its folded configuration). This is done by repositioning the boom arm.
“This multimodal robot can be used for building, cave and mine exploration, search and rescue, monitoring hazardous materials (e.g. Nuclear waste stockpiles; detection and disposal of improvised explosive devices (IEDs); weapons platform; toys; planetary exploration; monitoring the HVAC system.
“In a third embodiment motion is provided in harsh operating environments and uneven terrain by a spherical robotic that incorporates momentum exchange to achieve rapid acceleration/deceleration in all directions.”
The inventive spherical robot is capable of traversing a variety terrains, including pavement, asphalt, gravel, gravel, and mud. It can also be equipped with an amphibious capability that allows it to travel through mud, swamp, or open water. The present invention is different from other spherical robots in that the internal frame is attached to the external sphere, while the center mass of the robot remains fixed at the center. For momentum exchange, single-gimbaled control moments gyroscopes are used in an exemplary embodiment. This design is extremely agile because the momentum required to maneuver is stored in the CMGs. It does not require the use of large-torque motors (and large electrical power-consuming) like a standard direct-drive system.
“In one embodiment, the cubical frame contains four single-gimbal CMGs with each gimbal angle at one face. As an alternative to single-gimbal CMGs you can incorporate a variety of momentum exchange devices, such as reaction wheels or dual-gimbal CMGs. Robots are not restricted to spheres as outer structures, but can also be used in generalized amorphous and ellipsoidal configurations.
The inventive spherical robotic robot is useful in military operations, such as covert reconnaissance and munitions delivery. Robots can also be used in general commercial applications as a toy, or as a therapeutic device.
“The fourth embodiment of the multimodal robot is a wirelessly-controlled or autonomous vehicle which is an all-in-one system of ball retrieval, storage and throwing. This design features an integrated ball pick-up mechanism and a jai alai throwing arm.
To enable ball pickup, the robot’s body and wheels are separated to allow for automatic picking up and loading of target balls. The robot is driven towards the target using this method. The robot’s curvature directs the ball into the spaces between the wheel of the body and the wheel. The wheel rotates the ball, bringing it up for storage in a basket or another storage container.
The feedback circuit stabilizes the robot to throw. It acts as an inverted pendulum and balances upright. Because of the great rotational inertia, the robot can quickly change from a lay-down to an upright position. This allows for the efficient tossing of light-weight balls. As the ball rolls off of the throwing arm track, it is spun. This results in a longer and more stable throw.
“The robot’s potential uses include remote-controlled toy cars, an automated tennis ball retrieval system and a grenade rocket launcher.
The following four multimodal robots are described. They include locomotion via tracks or wheels and spherical rotation. Also, they can hop, climb, throw, and do spherical rotation. Although different embodiments use different locomotion methods, one thing that unites them all is the use of feedback to control the angular momentum. This allows for active balancing and changes in the orientation and movement of robots. This makes them versatile and can be used for a variety of purposes, from toys and military applications to industrial applications.
“First Multimodal Robot Embodiment”
“Referring first to FIGS. The robot 10 in the first embodiment is shown in FIGS. 1-3 and 6. Two independently driven wheels 6 and 8 are mounted on the ends two independently driven arm assemblies 12 and 14 that pivot around central leg/shaft 16. By using a non-backdriveable motorized leadscrew 20, the arm assemblies 12, 14 move linearly along leg 16. The screw 20 provides a gradual motion that allows the vehicle to change between an upright roving and toe-balancing configurations (on toe 15 at the ends of leg 16. FIG. FIG. 2 shows the three rotational directions that the inventive robot moves around. Leg 16 corresponds to the yaw-axis and the axles of drive wheels correspond to the pitch-axis. Arm carrier 21 defines the midpoint in arm assembly and corresponds to the roll-axis.
Referring to FIG. 2. Arm assemblies 12, 14 are connected to a central arm carrier 21, via joints 11-13, which extend through the leg guide channels 48-49. An arm carrier 21 is driven along the leg 16 using a leadscrew powered via motors in the arm carrier. This allows joints 11 and 13 to be moved along the lengths the guide channels.
“Left Arm Assembly 12 includes a Parallelogram Linkage, which has basic?frame? Elements of a top right arm 22, bottom left arms 23, left arm link 30 and left-arm mid-link 25, respectively. Right arm assembly 14 also includes the frame elements of top right and bottom right arms 18, 19, left arm mid-link 50, right arm end links 47, and right arm arm mid-link 51. Preferably, the frame elements of arms are made from lightweight but very rigid metals such as titanium or aluminum. The frame elements can also be made from strong, rigid plastics or other polymers. Below are detailed descriptions of the joints and drive mechanisms which allow manipulation of basic frame elements.
The top left arm 22 is attached to the arm carrier via joint 11. It attaches via joint 31 to the left arm link 30 via joint 31. The left arm endlink 30 is connected to the bottom left arm via joint 32, and to arm carrier 21 via joint 13, respectively. The left arm midlink 24 attaches via joint 4 to the top left arms 22 and via joint 21 to the arm carrier 21 via joint 13. All joints are revolute joints in all cases.
“The left spring lever 25 attaches to the left arm assembly via joints33 and 34. As shown, joint 34 is offset horizontally from the middle of a line connecting joints 31-32. Attachment between spring lever 25 & joint 34 is made up of a standard revolute and joint 34 coaxial joint. Joint 34 can be attached to either a linear bearing that travels along the line connecting endpoints 25 of the spring lever 25, or to a straight-line?Watts? Linkage 70 is described in FIG. 1b, which includes the links 60,61, and 62 as well as connecting joints 36 to 37, 38, and 59. The arm assembly 12 won’t move if the 25-gauge spring attaches to joint 34 directly without any form of linear bearing/prismatic or straight-line linkage. The left spring lever 53 attaches to the right arm assembly through joints 55 and 56. This is in conjunction with a Watts linkage.
“The torque applied to the left chain drive sprocket41 at joint 32 causes left arm assembly 12 to be actuated. Sprocket 41 engages with the output shaft 29 (not shown) of the arm motor 27. It is located centrally within the left arm link 30. The right arm assembly 14 can be similarly actuated. Right chain drive sprocket 39 engages the output shaft (not illustrated) of right-arm motor 51. It is located within right arm end link 47.
Two extension springs, 5, 52 connect the arm assemblies. Left spring 52 connects to the proximal arm spring lever 25 at joint 35 with the right spring pretension pulley 54 (visible as FIG. 3.) of the right assembly. The right spring 5 extends from the right arm spring lever 53 to the left spring pretension pulley 26, in the same manner. The spring tension can be adjusted by turning the spring pretension pulleys 26, 56 in the desired direction. This adjustment is made by applying torque to the arm motors 28, 51, while their respective arm motor clutches 28,44 are disengaged. The arm motor output shaft 29, (right shaft not illustrated), has a limited range of travel. This will eventually cause the arm motor body to rotate, 28, 51. The spring pretension pulley 26 and 54 are then engaged via a single-stage spur transmission.
“FIG. “FIG.4” illustrates the possible modes of operation for the inventive robot. The robot can be operated using the independently-driven wheels 6, 8 and 20 as well as the leadscrew 20, independently actuated arms 12, 14 and leadscrew 20, which can each perform a variety of useful functions. Horizontal roving (a), is when the right and left drive wheels rotate in the same direction to tilt one leg forward. To move the vehicle forward, the wheels must continue to drive in the same direction as before. The end of the leg should be on the support surface. The wheels can be used in opposite directions to steer. The wheels can be operated independently, allowing the robot to turn quickly at a point or with very limited turning radius. FIG. 13 Horizontal roving Mode gives the vehicle a low profile that allows it to pass under low obstacles such as wires or fences. It also helps to avoid optical sensors that are placed several inches above the floor or support surfaces.
“An uprighting maneuver (b), which is a horizontal roving mode, involves applying a sudden and strong torque to the wheels in a specific direction. The vehicle experiences equal-and-opposite reaction torque when the reaction wheels are torqued in one way. A strong clockwise torque causes a counterclockwise rotation of your leg to move it into a vertical position. Reaction control thrusters or simply by bringing the vehicle back into contact with the support surface can be used to blot off the motion of the reaction wheels. Reaction wheels only provide instantaneous torque, and this is limited by the motor that drives them. The robot is only able to drive in the upright mode using the reaction wheels. With the leg pointed up, it provides a support frame to mount vision systems and other sensors.
Reaction-wheel stabilization can be used for upright balancing and roving in the fore-aft orientation (c), toe-balancing, hopping (d), and toe-balancing. Reaction wheels can be used in the left-right direction as counterweights (similar to a tightrope walker?s balance bar). The reaction wheels can also be used as counterweights to the stiff elastomer Spring to prevent the vehicle from hopping in conventional monopedal locomotion or cartwheeling monopedal loomotion (f), (g).
“The wheels must have a significant mass to enable the three last functions (e,f and g), to work. The vehicle batteries 7 provide the mass for each wheel in the exemplary embodiment. They are distributed symmetrically around each wheel’s outer hub and the motors 45 within their respective motor housings 9. These motors drive the wheels 6 through 8. The robot’s overall weight can be reduced by utilizing the relatively heavy components rather than adding weight to the wheels.
“The independently-actuated arms 12, 14 can function both as a hopping mechanism when rotated symmetrically about the central leg 16 (around the roll-axis) and as an actively-controlled roll-axis stabilizer when rotated anti-symmetrically about the central leg. FIG. 5a shows a hopping motion. In FIG. 5a, a hopping motion is made by starting with an arm arrangement that has the arms angled downwards (indicated in FIG. 5a – Slowly rotating the arms 12, 14, symmetrically upward relative the leg 16, and abruptly halting when they reach horizontal orientation. A few level sensors (not illustrated), may be found on the leg 16 and/or the arm assemblies 12, 14, to generate electrical signals which are sent to the vehicle’s control unit (not shown). The controller could be integrated in one or more commercial and/or off-the-shelf (COTS) printed circuit board (PCBs) as an example. This includes the Texas Instruments C200 MCU. The protective housing should be attached to the leg 16 so that it does not affect the operation of the leadscrew. The level sensors can provide feedback to help control the antisymmetric arm motion to balance. FIG. FIG. 5b shows that anti-symmetric arm motion generates a similar and opposite torque around the leg 16 which allows feedback stabilization around the roll-axis. The robot can simultaneously stabilize and hop in roll-axis plane if these two motions are properly superposed. To allow the arms to hop and balance the vehicle effectively, the majority of its mass should be concentrated at their ends.
“The preferred embodiment’s leg 16 should be made from a lightweight material with sufficient stiffness to prevent buckling and allow for structural flexibility. Aluminum, titanium and lightweight steel are some examples of suitable materials.
The wheels 6, 8 provide pitch-axis stability when out of contact with the ground. They do this by actively applying torque using the same principle that the arms. Parallelogram linkage is used to ensure that the arm assemblies 12, 14 have an angular alignment of 6/8 relative to 16 at all times. This reduces coupling between the pitch and roll-axis dynamics, simplifying the overall dynamics. To prevent interference between coplanar elements, the top and bottom arms 18, 22, and 19, 23 respectively should have an outward curve at their lengthwise centres, as shown in this diagram. The arm sections’ ends curve inwardly relative to their midpoints. For small angular deflections (+/?15, the wheels could be attached directly to one link.
“In the preferred embodiment, the left and right arm motors 28, 51 are high-speed/low-torque in order to optimize hopping performance. To support the weight of both the arms and recover energy while hopping, the arms are spring-loaded with extension springs 5 52. This spring mechanism must resist movement of one arm relative the other to support the weight of wheels during hopping. However, it shouldn’t substantially resist rotation of either the central leg or arm. This arrangement permits the active roll-axis stabilization to be achieved by allowing for anti-symmetric rotation.
While a torsion-spring across the arms meets these basic requirements, more functionality can be achieved through a more complex linkage mechanism. Specifically, since each arm is actuated by torque applied at one of the outward joints by the corresponding high-speed/low-torque motor 28, 51, a digressive stiffness (decreasing with increasing deflection) is desirable in order to provide a more constant resistance to symmetric motion; i.e., provide high support at small deflections, without overwhelming the motors at large deflections. To facilitate multimodal operation, it is preferable that the spring rate can be adjusted on-the-fly without creating torsional bias/asymmetry. The arms should be able to self-lock to a fully-tensioned position without additional actuators in order to store energy during large jumps and to prevent the vehicle from being folded during roving. To prevent collisions between coplanar mechanism link links, the angle at which locking takes place must be less that 90 degrees.
“The preferred embodiment incorporates a pair non-coplanar springs 5, 52 that are attached to spring levers 25, 53 in the parallelogram linkage. This creates a self-locking feature. FIG. 7 illustrates the relationship between springs 5, 52, and levers 25, 53. FIG. 7 shows the relationship between the springs 5, 52 and levers 25, 53. The FIG. 7 diagram shows the top plane. 7 includes right spring 5, left Spring lever 25, and joint 34′, which includes joint 34 & Watts linkage 70. The bottom plane is shown in the middle of the figure and includes left spring 52 and right spring lever 53. It also includes the joint corresponding left joint 34? which includes joint 55 with its Watts linkage (or another appropriate linkage). The respective joints are identified in FIGS. 1-3. FIG. FIG. 8. illustrates the kinematic equivalent realizations for the arm suspension mechanism in FIG. 7.”
“As shown by FIG. 9 shows that the resistance to symmetrical motion decreases with increasing horizontal deflection (arms outstretched as in FIG. 1), which is measured as the angular displacement (??L=?). 1), measured as angular displacement (?L=?). Eventually, the sign changes sign beyond a certain critical angle. In the plots. The arms lock into a fully-tensioned state, provided the arms are not allowed to deflect beyond this critical zero-torque angle. FIG. 9 shows the relationship between angular displacement and percentage spring stretch, resultant torque (in Newton meter) and effective torsional spring rate (in Newton meter/radian), respectively. FIG. 9 shows the angular displacement relative to percentage spring stretch, resultant torque (in Newton meters) and effective torsional rate (in Newton meters/radians) at four levels of spring pretension. FIG. FIG. 10. This shows the resistance to antisymmetric rotation under different levels of spring pretension. It uses the same comparisons as FIG. 9. FIG. FIG. 11. This plot shows the critical zero-torque angle (locking) as a function varying link lengths forsymmetric rotation. B/L=0.125; C/L=1.094; and D/L=0.438.
“Note: The symmetric configuration allows bi-directional series elastic actuation with the extension spring. Referring to FIG. Referring to FIG. 12, the left arm motor 28’s main body is kept stationary by a small, actuated clamp 62 during normal operation. The motor 28’s body can rotate by loosening clamp 62. This allows the left spring pretension pulley 27 to rotate around the one end. To adjust the tension on the spring 5, right arm motor 51 can be turned by loosening the clamp that is not visible in the figures. These features allow springs to be pre-tensioned, while the arms 12, 14, are locked at their maximum travel. To do this, loosen the clamps 62 and drive the motors 28, 51 in the opposite direction to cause downward arm motion (to prevent unlocking). The springs 5, 25, are always under tension. You can tighten them by driving the pulley 27, 54 in either of the directions. The motors 28, 51 can also be actuated in series with the springs 5, 25, by loosening their clamps. This is often called a “series elastic actuation”. This may be used to buffer mechanical energy and protect motors 28 and 51 from mechanical shock.”
“As mentioned above, each drive wheels 6, 8 have two motors that propel and steer the vehicle (via differential drive), when it comes in contact with the support surface. Referring to FIGS. Referring to FIGS. Drive gears 45 and 45 engage spur gear 40 which is mounted on axle 46. The batteries 7, which provide additional weight for monopedal, hopping, and balance, are mounted on each wheel hub. Drive wheel 6 is on the left with two motors 45 and spur gear 42. These drive the wheel around the corresponding axis.
“In another embodiment, the drive wheels can be replaced with a second set or arms that are mounted in an orthogonal configuration with the arm assemblies 12. This creates a pair of pitch-axis arms and a pair of roll-axis arms. To provide feedback on anti-symmetric arm motion, level sensors can be installed within the pitch- or roll-axes. This structure can allow for monopedal locomotion with high stability that can be balanced in multiple axes. To provide the required mass for hop and toe balance, the weights of the drive motors and wheels are eliminated from this design.
The multimodal robot can be equipped with audio, thermal, chemical, and optical sensors. A transceiver can be added to the electronics of the vehicle for remote commands and information transmission.
The robotic system described in this article is capable of maneuvering in complex structures and rugged terrain using a variety of combinations of hopping. Pole climbing, toe balancing, horizontal walking, uprighting, and pole climbing. All done in a controlled manner. The robotic system can be used to climb stairs by using toe balancing and pole climbing.
“Second Multimodal Robot Embodiment”
FIGS. A treaded vehicle can perform stable heel and toe standing (i.e., ‘wheelies?). able to balance on the edge or similar elevation change. FIG. 14a The multimodal robot 100 comprises a pair 110 and 120 of arms that each have their own tread assemblies. They are attached to chassis 101 via tread shaft 108. The exemplary embodiment contains all the electronics and batteries needed for operation and communication. Rotation of the shaft108 causes the tread links 108 to move for translational movement. Rotation around the shaft causes the whole tread assembly to turn with respect to its chassis. This unique “hip joint” is described below. Below is a detailed description of this unique?hip joint? Optional platform 104 can be attached to chassis 101 to allow for attachment of sensors, cameras or other equipment to the robot. A housing can be used to protect the chassis, any electronics, batteries, or actuators, where there is no platform. If platform 104 is present, the chassis housing may be one structure. In this illustration, chassis 102 is separated by a dashed line. The chassis housing can also be enclosed within the platform. Platform 104 does not have to be rigid. It can be either a rigid or deformable structure that can be passively or active deformed to allow the robot to be used for specific tasks. The platform does not have to be enclosed. It can be open or combination of open and closed sections.
“One or more sprockets can be driven by an actuator, such as a motor or engine, pneumatic turbine, or motor. FIG. FIG. 14b is a simplified diagram that shows the components of a tread-assembly with the side cover removed. Each tread assembly contains two or more treadsprockets (114, 116) that are rotatably mounted on a vertical sideplate or frame 111 in order to engage tread 112. Frame 111 may also have one or more tread guides. Tread sprocket114 is coaxially mounted with shaft 108. Mounting a sensor to measure speed, position, or torque may be possible for either sprocket 114 or both. Optionally, a force sensor or pressure sensor can be mounted underneath the tread 112 in order to determine where the tread assembly contacts the ground or another surface. You can also include mechanisms that adjust the tension of your tread, as is known to the art. Control electronics, batteries and communications electronics can be installed within the tread arm 110 or within chassis 102, platform 104, depending on the situation.
“Referring briefly at FIGS. 20b and 20c, wheels 124 can be mounted rotatably near the edge of platform104, opposite to the chassis, in order to expand the robot’s functionality. FIG. FIG. 21a shows the robot maneuvering in a narrow passageway, such as a duct 128. The robot effectively binds itself between the sides of the tunnel. The robot can apply pressure perpendicularly to the duct side using the wheels 124 as it moves along the length of duct. To provide feedback to the robot’s controller, sensors within the treads and attached to the tread shaft can be included. This will allow it to adjust the relative angles between the chassis/treads in order to maintain the required pressure to allow it to move through the passageway or duct. For additional control, the wheels 124 can be attached to allow them to freely turn around their axles or may be attached directly to the shaft of one or more motors.
“A variation of FIG. FIG. 14a illustrates a variation on the embodiment of FIG. 17 where the tread assemblies have been replaced by a corresponding wheel arrangement, which comprises two or more wheels, 117, 118, that are rotatably mounted in planar relation on the arms 119. Toe balancing, or other maneuvers that require force to apply at the distal or tip of the arm 119 can be performed in this embodiment. Axle108 extends from chassis 101 as described above to drive wheels 120. These are the details of the robot’s “hip joint?” The maneuvers and movements that can be achieved by this joint are equally applicable to FIG. 14a and FIG. 17.”
“Referring FIG. “Referring to FIG. 19, in the preferred embodiment of FIG. 19, a two-degree of freedom joint is used in a mobile robot. 14a connects each arm 110, 120, or 119 in the wheeled model to the chassis. It transmits two coaxial torques, but they are decoupled. To transmit the torque needed to rotate the wheels 112, 122, the tread shaft 108 is connected to the motor 140 at one end via coupling 138 and the other end to the drive sprocket (or wheel). The shaft is able to pass through the tread gear 130 which is fixedly attached to the arms 110 to 120 (or 119). The pinion gear 130 is mounted to a second shaft 136, parallel to the tread shaft 110. This causes the pinion and arms 110, 120 (or 119) to rotate relative to the chassis 102. It can be driven by coupling 138 by the second motor 142, also known as the boom motor. As will be explained below, this assembly allows for adjustment of the center-of-gravity. The slip ring 144, which may have one or more channels, can be coaxially located with the first shaft. It transmits and receives power and/or electric signals between the chassis and arms 110 (or 120) during a continuous range in rotation. To provide feedback to the control system, optical encoders 134 can be used to measure the angle between the chassis and arms 110, 120 (or 119) to determine the angle. Alternately, all components of the hip joint (i.e. motors, gears, and sensors) may be located within the arms. In this case, the chassis could be simply an axle that connects the shafts 110, 120, or 119 together.
“The embodiments shown in FIG. “The embodiments of FIG. 14 and FIG. This allows the robot dynamically adjust its center gravity. Commercially-available MEMS accelerometers and gyroscopes, coupled with advanced filtering techniques, allow the robot to estimate its angle with respect to gravity. The multimodal robot, illustrated in FIGS. 110 and 120, can be balanced upright with the arms 110 and 120 extended from the body (with respect to tread shaft 108) as shown in FIGS. 15b and 20c allow for a significant increase in the range of an instrument or sensor on board, such as a camera. A robot with tread assemblies measuring between 10-15 cm and 30-50cm in height may be capable of standing up to 65cm tall and overcoming obstacles that would otherwise prove impossible with a robot only 10-15 cm tall. This inventive design can also be used to cross chasms almost as large as the vehicle’s by moving the arms in opposite directions. 15c and 20b The front-mounted pivot on the chassis can be used to dampen vibrations while driving over rough terrain quickly. Because the arms can be reconfigured, there are many modes of locomotion that the robot can choose from depending on the terrain. FIG. FIG. 15a and FIG. 20d show how the robot can balance on the proximal (with respect to tread shaft 108) end of its arms. FIG. 15a and FIG. 20d, the robot can balance on its proximal (with regard to the tread shaft 108) arm end. This means that the robot can perform a wheelie with the proximal 110, 120 end in contact with ground, but neither the chassis 102 or the distal end the arms in contact. This is known as the “V-mode”. You can change the angle between chassis 102, arms 110, 120 by activating the boom motor. The tread motor will then be actuated as necessary to maintain the changing center of gravity above the contact point. This will prevent the robot from falling to the ground. The robot may change the angle in response to a reference command, or it could be performed by an operator. This maneuver can be used, for instance, to start a climbing sequence. FIGS. FIGS. 15b and 20c show the robot in a toe-balancing mode, also known as a?stoppie?. This is achieved by placing the distal ends of the arms 110 and 120 in contact the ground, but neither the chassis 102 or the proximal end of the arms are in contact the ground. This is known as the “C-balancing mode”. You can change the angle between chassis 102, arms 110, 120 by activating the boom motor. The tread motor will then be actuated as necessary to maintain the contact point’s changing center of gravity. The robot may change the angle as a result of an operator’s reference command, or it could be performed automatically in response to an external stimulus. The robot can use multiple locomotion modes according to an inventive mechanical design and feedback control algorithms to get around obstacles such as stairs and rubble. However, the robot is small enough to maneuver in tight spaces and save weight and cost. A preferred embodiment of the electronics on board includes wireless communication circuitry as it is known in the art to enable bidirectional communication via WiFi. A preferred embodiment includes the appropriate electronics and programming that enable the robot communicate with other computers, robots and mobile devices using the IEEE 802.11g standard.
FIG. 2 illustrates some of the complex tasks that can easily be accomplished by a treaded/wheeled robotic robot. FIG. 21a, which was previously discussed, and FIG. FIG. 21a, which was discussed above, and FIG. Small surfaces such as a stair edge (126), a branch or a telephone line or power line, are ideal. The robot’s treads are in contact at one point with the surface. The robot adjusts the boom and chassis to maintain its center of gravity and keep it in line with that point. To determine the contact point, inertial sensors, such as accelerometers or gyroscopes, may be combined with contact sensors (e.g. force sensitive resistors) within the tread assemblies. The combination of the tread motors and the balancing motors, as well as continuous feedback from sensors to control them, provides active balancing to stabilize the robot’s position. When the robot climbs up or down stairs, the center of gravity shifts in the desired direction. 126 This is done so that the contact point is directly above the robot’s center of gravity using a variety of movements.
“FIGS. 22a and 22b are two examples of the operations that can be performed by the multimodal robot described above for climbing obstacles such as stairs. Step 160 is where the robot approaches the step and balances on the distal end (in?C?balancing). FIGS. 15b and 20c respectively. Steps 162 and164 are where the chassis position is adjusted upon reaching the step so that the center mass is directly above or below the edge of first step. The robot balances on the edge and gradually moves up the step using a combination of tread actuation, appropriate angle variation between the treads, and chassis adjustment.
“In one embodiment of this maneuver, the angle between treads and chassis is actuated using a function time. This is to maintain the center of mass above the edge of step and maintain the desired angle between chassis and horizontal. The contact point between treads, the edge and treads moves (relatively slowly) along an arm. Balance is then achieved by feedback control via tread actuation. Feedback control is used in a second version of the maneuver. This involves a combination of tread actuation as well as small adjustments to the angle between treads and chassis.
There are two possibilities when the vehicle reaches the top of a step. The first is that the angle between the edges of successive steps and the angle of horizontal of the chassis is greater than the angle of horizontal of the chassis (that is, the angle at which the steps are relatively narrow). The vehicle will continue forward motion in either case, returning to C-balancing mode after reaching the top. The situation will be the same if it reaches another step.
The second scenario is where the vehicle does not reach the top of the stairs and the angle of successive steps is relatively low. The angle of the chassis as it approaches the top of the current step from horizontal may be almost the same angle as the angles of the edges from the next steps from horizontal. This will allow the vehicle’s proximal end to reach the edge at the next step without contacting the edge of step 8. You can adjust the center of mass to reach the edge of the next steps (9) or (10). The process described in steps (4) through (7 are repeated as illustrated in steps (11) and (15).
You can use the following steps to move the robot in the desired position for a task. This and other similar tasks are possible because the robot can operate, or can be operated to, shift its center gravity to balance on a small point. It does this by changing the angle between the chassis and the arms, and using the treads and wheels to?catch’ itself. Before it falls.”
The multi-modal robot in the second embodiment can perform a variety of maneuvers using a minimal number of actuators. This saves cost and weight. You can mount additional sensors internally or externally. These include contaminant sensors and Global Positioning System (GPS), receivers, wind sensors. Analog or digital cameras, optical, radiation, or optical sensors. Mobile robot platforms 104 and arms 110, 120, and 119 can be equipped with end effectors. These include linkage mechanisms that have a gripper, liquid or solid collection systems, lighting systems, weapons systems, and other devices.
FIGS. 16a-c . This configuration still allows for shifting of the center gravity, but the method of shifting is different.
“In this embodiment, the robot is equipped with a chassis 148 as well as an actuated boom 150. The chassis 148 is driven using a pair of treads (152, 154) or conventional wheels (156), as shown in FIG. 18). The 150-pound boom has significant mass. The boom’s mass is roughly equal to that of the chassis in the exemplary embodiment. The robot is equipped with motors to drive the treads or wheels and adjust the angle of the boom 150 in relation to the chassis 148.
“The hip joint as described above, with reference to FIG. 19. may be added to the configuration that uses a boom to shift the center of gravity. The boom motor, which corresponds to the balance motor, will turn the boom arm.
“The second multimodal robot embodiment has sensors that detect the robot’s configuration. The vehicle can balance on its front and rear cogs or wheels by applying feedback control. You can also use the vehicle to climb over obstacles, including stairs. To do this, extend the mass of 150 pounds over the obstacle and rotate the chassis upwards and back. The maneuver can be performed in either a statically stable or dynamically balanced way. The boom arm can be extended and/or configured with wheels or treads in a similar fashion to the wheels 126 in previous configurations.
“As with the first multimodal robot, the configuration with the Boom 150 takes advantage the weight of the battery to be used as a functional mass. To transmit power from the batteries to motors within the chassis, an electrical connection is created between the boom and chassis. This connection is made using slip rings, which are steel shafts mounted in bronze bushings. The boom can be rotated around the chassis without restriction by the slip rings.
“In this configuration the robot’s treads are in contact at one point with the surface. The robot then maintains its balance by moving the boom so that its center of gravity is in line with the contact point. Inertial sensors (e.g. Contact sensors, such as accelerometers or gyroscopes, can be used together with them (e.g. To determine the contact point, force sensitive resistors are placed inside the tread assemblies.
“The second multimodal robot design uses multiple commercial off the shelf (COTS) sensors, including MEMS-based accelerometers (and gyroscopes) and optical encoders (134 (shown at FIG. 19) To estimate the angle between the chassis and gravity (in FIG. 14) and the angle between the boom arm and the chassis (in FIG. 16). Programming the robot involves a control system, which may include a Kalman filter, to activate the motors to balance it dynamically. The prototype accepts manual input via the COTS radio frequency remote.
“In one application, the second multimodal robot embodiment was used to create an ‘army? One application of the second multimodal robot embodiment was to deploy the robots in an open area (a parking lot), where plumes of colored smoke were released. Each robot was outfitted with electronics and a sensor pack to measure smoke concentrations. These measurements were sent in real-time (via WiFi or 3G cellular data connections) to an off-site supercomputer that ran advanced weather-forecasting algorithms. These algorithms then synchronized a numerical simulation (or smoke plume) with actual field measurements in real-time (a problem called data assimilation). Then, the vehicles were told where to go next to reduce uncertainty in the forecast. The system was successful in achieving its goal. It was able to predict where the smoke would go and coordinate the vehicles to gather the best information for each wind condition. The research has important social relevance related to new technology and algorithms for tracking a wide variety of environmental plumes of interest, from gulf-coast oil, to Icelandic volcanic ash, to possible chemical/radioactive/biological plumes in homeland security settings.”
“Third Multimodal Robot Embodiment”
“In a third embodiment, the spherical robot incorporates momentum exchanging devices to achieve rapid acceleration and deceleration in all directions.”
“As illustrated at FIG. 23 illustrates an example embodiment of the spherical robotic robot according to the invention. A frame 202 supports a plurality momentum-exchange element 204 so that they are distributed relative to a surface of a sphericalshell 210. The frame 202, elements, 204 and all electronics, actuators, and batteries required to power and control it. To optimize balance and locomotion in different environments, sensors may be added. Wireless communication devices may be included in the control electronics to allow communication with a remote computer or mobile phone. The spherical robot can also be tied to a controller such as a joystick or track ball, or any other external control device.
FIG. 2 shows the basic elements of three momentum exchange elements that could be used in the SPHERICAL ROBOT. 24a-24c . FIG. 24a contains a single motor to spin the wheel. FIG. 24b . This assembly contains two motors. One for spinning the wheel and the other for rotating the gimbal. This allows for a variety of angular momentum. FIG. FIG. 24c shows a double-gimbal control moment (DGCMG), with three motors including two motors used in the SGCMG and a third to adjust the plane on which it sits.
“In FIGS. FIGS. 23 and 26 show the configuration of the fourth embodiment. To achieve the desired function, the SGCMGs can be operated separately or together. Frame 202 is shown as a cubical shape, but it can be made with any geometric shape that fits within the spherical shell. This includes conical, pyramidal, symmetrical, skewed and linear arrangements with 3-D structures. FIG. FIG. 25 shows a few examples of the many possible combinations of momentum exchange elements. These include a pyramid and skewed cone as well as a symmetrical octahedron and roof-types with linear combinations. Any geometrical shape that allows momentum to be generated can be used. This includes a variety of directions that allow for steering, rolling and balancing. The robot’s outer structure is not limited only to spheres, but can also include generalized amorphous and ellipsoidal configurations.
“FIG. “FIG. 26” shows a three-dimensional illustration of an exemplary implementation for the inventive spherical robotic system. The frame 202 should fit snugly within the spherical 210 shell, as illustrated. If the cubic frame is used, the corners may be chamfered as shown to give the shell 210 a wider, more rounded surface that contacts the frame. This ensures that the shell 210 has a uniform structural support and that the frame 202 as well as the components that are mounted on it are stable supported.
“As illustrated in FIG. 2, each SGCMG204 a-d contains the spin motor. (The shaft of the spinmotor 220 can also be seen in FIG. 26), and reaction wheel in a small cylindrical housing. The spin motor can be seen in FIG. Each gimbal-axis has a shaft attached to it. The other end is supported by a pivot, so that the reaction wheel and axis rotate when they are driven by the respective gimbal motors.
All electronic components necessary for operating, communicating with, or collecting data will be contained within shell 210. It is best to center the frame 210 so that the weight is at the center. These components may include one or several printed circuit boards, as well as battery casings, or other holders. The components may be supported on a plate or bar that extends between the corners of the cube, or between the upper and lower faces 208 e of the cube, as illustrated. This will not interfere with the movement of elements 204. If the frame is hollow, some components, such as the batteries, can be mounted inside the frames’ edges. Alternative embodiments of elements 204 can be mounted on all six faces of the cube or on any face of a chosen geometric structure as long as there is enough space to prevent interference with movement of momentum exchange elements.
“FIGS. 27a and 27b show an alternative construction of spherical robotic with the outer shell removed. The intersection of four open-centered discs 234a-d, which correspond to faces 208a-d in FIGS, creates frame 232. 23 and 26. Additional structural support is provided by the sphericalshell’s rounded faces. Attached to the top of frame 236, is the top housing 236, which houses the control electronics.
Referring to FIG. “Referring to FIG. 27b, which shows an exploded image of the complete assembly with one SGCMG, also in exploded views, the frame is defined as the assembly of faces 234 a-234d with top plate 244 e bottom plate 245, which are attached using brackets 242. A number of battery holders 240 are attached to the top surface of top plate 244 to hold the 238 retaining batteries. The batteries are button-style lithium batteries. Additional battery holders 240, 238 and 238 can be found on the outer surface 245 together with the gimbal motor controllers 244.
“FIG. FIG. 27c is an exploded view showing SGCMG250. 27b . Attached to the shaft 270 is the rotor 268. The rotor is responsible for providing the inertia necessary to store momentum of a SGCMG. The outer housing is formed from 256, 259 and 260, 260 and 267, 267 and 272, and held them in place by the rotor and the rotor shaft 268, 272. They are also held in place by the journal 252, 277, thrust bearing 258, 271, and combination of 258, 272. Attached to the shaft of the spinmotor 254 is the rotor shaft 275. The spin motor 254 attaches to the cring 252, which is attached to bottom plate 256. The spin motor 254 rotates rotor 268 at the same rate as the SGCMG or VSSGCMG cases. This is done via feedback from the optical encoder 282 and spin motor electronics 282. The optical encoder 280 attached to the top plate 276 is used to measure the rotor speed. Mounting posts 279 are used to mount the spin control electronics 282, which are attached to the top plate 276. Attached to the housing assemblies 256, 259 and 260 are the gimbal shafts 268, 267, 276, 278. Attached to gimbal shaft 269, a spur gear 262, with a thrust/journal bearing combination, is a one-gimbal shaft. The spur gear 262 is kinematically bound to a second spur drive 263 that is attached to gimbal motor 261; it is also free to turn relative to right gimbal mounting bracket. The slip ring assembly 274 holds the second gimbal shaft 273. It is rigidly attached to it and can rotate relative to the left-gimbal mounting bracket 266, via a thrust/journal bearing combo. Despite the continuous rotation of gimbal, the slip ring assembly 274 supplies power to the spin motor controller 282 A potentiometer 273 measures the angle of rotation of the gimbal shaft 273. It attaches to the gimbal shaft while the immovable part attaches to the left gimbal mounting bracket (28) Attached to the sidewall 234 are the right 276 and left 264 gimbal brackets.
“In one embodiment, the robot may be equipped with pressure bladders that are attached to the shell 210’s inner surface or at non-interfering places on the frame 202. FIG. 23 shows an illustration of a single pressure bladder (214). 23). 23. The momentum exchange elements allow the buoyant robot, which spins as it moves, to travel within or above the water’s surface. This makes it an amphibious vehicle. One implementation allows the bladders to be filled to the desired buoyancy before the robot is deployed via a valve through the shell. Another approach is to mount small, compressed gas canisters on the frame. These can be used in buoyancy compensators and life vests. A feedback system will communicate with the frame to determine the conditions of the body of water. The system will control the gas release into the bladders in order to achieve the desired buoyancy. This will allow the robot to maneuver efficiently and effectively. The bladders can also have bleed valves that allow for active adjustment of buoyancy in response to changing conditions. After a few uses, the gas canisters can be replaced with new ones.
The robot can also be made passively buoyant by selecting the right material. The frame can be made from lightweight materials such as plastic, wood, fiberglass or titanium, depending on its strength and durability. You can use hollow or partial-hollow materials for the frame, such as honeycomb structures, extruded channels, or honeycomb structures. A shell could be made from either a buoyant polymer or buoyant plastic, such as neoprene, polystyrene or closed-cell foam. It should have a continuous surface that is watertight. For applications that require metal, the buoyant foam structure can be covered with an impervious or coated outer skin, such as a lightweight metal or epoxy resin. This construction is similar to what you see on surfboards. To seal the openings (ports and doors) in the shell that allow access to the interior components of robot, it would be necessary to make sure they are watertight.
“FIG. “FIG. 28” shows a block diagram showing an exemplary control structure that can be used in conjunction with the spherical robotic arm. Other control architectures are possible, as will be obvious to those skilled in the art. You can achieve the path generation block by determining the relationship between the velocity and the angular rates. The ACS control block, pseudoinverse CMG steering block and gimbal angular rates controller block can all be derived using methods and algorithms that have been developed in the art.
“Locomotion in a liquid body can be achieved by activating momentum exchange elements to turn the robot’s body in the desired direction, just like on land. FIGS. FIGS. 29a-c show different uses of the spherical robotic arm. FIGS. 29a and 29b show a free-surface and near-a-surface cases, respectively. FIG. FIG. 29a shows that in fluids, the RWA spins counterclockwise, and the sphere rotates clockwise. The fluid’s interaction with the rotating sphere causes the sphere move in translation to its left. This is determined by the Navier-Stokes equations. These equations show that a rotating circle in an incompressible viscous liquid near a wall or free surface can move in a translational orientation orthogonal to the fluid’s angular rate, and parallel to the wall. See. J. Happel, and H. Brenner, Hydrodynamics with Low Reynolds Numbers: With Special Applications to Particulate Media, Springer 1983. This reference is incorporated herein. FIG. FIG. 29b, which is movement on top of a substrate, shows that when the RWA spins in one direction (clockwise) the sphere spins counter-clockwise (counterclockwise) propelling it to the left.
“A plurality spherical robotics can be used in conjunction to enable locomotion and overcome various obstacles. FIG. FIG. 29c shows a series of steps for stacking several spherical robotics in order to raise one or more of them. This gives the robot(s), at the top, an enhanced view to collect visual information and/or perform other tasks that might require overcoming obstacles. Three spherical robots (designated as A,B, and C) are placed side-by-side on a support. To squeeze robot B up in step 2, robots A and B move towards each other. Step 3: A and C are joined with B balanced on top. Step 4 adds robots D, and E to the mix. C and E are moved towards each other to push D upward. To keep B on top, A will move with C. After C and E have joined, step 5 sees B and D on top. F is forced upward by F when F’s spherical robots F, G, and E. In step 6, F, D, and D are joined on top of E, A, C and E. In step 7, D, D, and F move towards each other to push D upward. Step 8: D moves to the right and climbs up on F, while B moves to the left. Step 9 shows how the multiple momentum exchange components of each robot allow D to balance on top F, which then balances on top E. The spherical robots can be stacked to position a robot equipped with a camera or another sensor to view over obstacles. The spherical robot can approach obstacles with a low profile and still be able to work with similar robots.
“In an example application, multiple spherical robotics can be deployed with each robot carrying a different payload or instrument. Robots deployed together can work in concert to allow the robot carrying an instrument to be at its best position to complete its task. The above-described spherical robotic can be used for covert reconnaissance and munitions delivery in military and law enforcement applications. The robot can be used commercially as a toy, or therapeutic device.
“Fourth Multimodal Robot Embodiment”
“FIGS. 30-36 illustrate a fourth embodiment of the multimodal robot, which is a wirelessly-controlled vehicle that can perform the tasks of object retrieval, storage and throwing. This design features an integrated ball picking mechanism and a throwing arms. The fourth embodiment, although it is described as a ball-handling robotic, can be used to pick up and throw any other objects that are sufficiently symmetrical to enable the pick-up mechanism. The throwing arm, which is described as “jai alai” in the example, can be modified to take different shapes depending upon the speed, trajectory, and spin of the object being thrown.
The robot’s body and wheels are designed to automatically pick up and load target balls. This feature allows the operator of the robot to steer it towards the target by using the curvature and rotation of the wheels. The wheel rotates the ball, allowing it to be placed in a basket or another storage container.
“To throw, the robot is stabilized using a feedback control circuit. It can balance upright like an inverted pendulum. Rotational inertia generated by the motors driving the wheels allows the robot’s body to be rotated quickly from a laid-down to an upright position. This allows for the efficient tossing of a lightweight ball. The unique shape of the throwing arms gives the ball a spin as it rolls off the track. This results in a longer throw and more stability.
“As illustrated at FIGS. “As illustrated in FIGS. 30 and 31, the fourth robot embodiment 300 has a molded body 302 which is roughly cylindrical (circular when viewed from the side), with a diameter (between the wheels), and a width (between them) of approximately three times that of the target object. The pingpong ball is the target object in the exemplary embodiment. It has a diameter around 40mm. Two coaxial wheels 306 can be mounted on a rotational axle 303. Each wheel 306 can be driven independently by a motor (not illustrated). This motor is responsive to active feedback controls that provide the robot with a selfbalancing function. The control electronics that receive feedback and activate the motors are housed on a printed circuitboard (not shown), which is covered by a removable cover 309. A number of batteries, not shown, are located in the lower part of body 302, just below the rotational direction 303. They can also be accessed through the back cover 303. The robot’s center of gravity is located above the rotational direction so that the motors and electronics are not switched off, it will fall over.
The vertical arm 304 can be used as a track to launch the object and as a mass that allows for backward and forward movements through leaning. The track in the exemplary embodiment has a curvature similar to that of a jai alai Cesta (basket). To restore vertical balance, the robot moves forward when it leans forward. The wheels are rotated in opposite directions to facilitate turning.
Summary for “Multimodal dynamic robot systems”
Robots can be used for everything from material transport in factory environments to space exploration. Mobile robots are being widely used in the automotive industry. Robots move components from the manufacturing stations to the assembly lines. These autonomous guided vehicles (AGVs), which follow a track on a ground, are able to avoid obstacles and avoid collisions. In recent years, attention has been given to autonomous mobile robots that can be used for space exploration and sample collection, such as NASA’s Mars Exploration Rover. This has led to the advancement of mobile robotic technology and an increase in effectiveness of mobile bots in a variety of applications.
“Mobile robot technology has been largely focused on robot designs that have wheels to move. This has allowed for advancements in the planning and control of the rolling wheels. Despite these advances, wheeled mobile robots still have serious shortcomings that have yet to be addressed. Wheeled robots often have trouble traversing uneven terrain. This problem can be solved by increasing the wheel size. However, increased wheel sizes can have undesirable consequences such as an increase in overall size and weight. Additionally, increasing the size of the wheels does not always result in an increase in payload capacity or other operational features. The harsh operating environment of chemicals and heat can also negatively affect wheeled robots.
U.S. Patent Publication No. 6285 A1 describes a variation of a wheeled robotic that can address certain problems found in harsh environments. 2008/0230285A1 shares partial inventorship with this application. This application is incorporated by reference. It describes the first vehicle that combines wheeled locomotion and hopping. Multimodal robots can be used to add hopping and climbing capabilities to wheeled robots by attaching an axle to a central leg. This allows for relative movement between the axle and leg to lift the axle. You can create a hopping effect by using a sudden downward force to push the leg against the support surface. To climb the stairs, apply a steady force against a support surface. Additional stability is provided by the leg for moving across uneven terrain. One embodiment of the multimodal robot’s wheels is mounted on independently-moving parallelogram linkages that allow the wheels to change relative orientations or tilts.
The rolling robot is an alternative to the wheeled robotics. Rolling robots are those that roll on their entire outer surface, rather than external wheels or treads. They are cylindrical or spherical in shape and only one axle (if any) and an outer surface that is actively involved in the robot?s movement. All state-of-the art rolling robots work on the principle that the center of gravity of a wheel/sphere is moved. This causes the wheel/sphere to fall in the desired direction and roll along. Rolling robots offer many advantages over wheeled ones. They can travel on any surface, even water, and can move in any direction.
“Improving methods of locomotion is necessary to enable robotic systems to move in environments that are not possible for current-used robot locomotion designs. These improvements are described in the following description.
“It is a benefit of the invention to provide a multimodal robotic system that can operate efficiently on difficult terrain and/or in harsh operating conditions.”
The robotic systems of the invention are described as having a frame or body that has two or more wheels that can be mounted on it. Each wheel is driven by a motor. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The signals can be generated for forward, backward, or balancing motions. The power source provides power for the drive motors, the system controller, and any or all of the sensors.
A robotic system according to one aspect of the invention includes a frame that has two or more wheels mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source provides power for the drive motors, the system controller and any or all of the sensors. Each arm has a distal end where a wheel is mounted. A proximal and a centrally placed leg are located between the arms. The proximal ends of each arm are rotatably attached at the leg. An arm motor is mounted on each arm to drive the rotation of an arm relative to the leg. This is so that the legs are arranged vertically with one end in contact to a support surface. (i) Downward symmetrical rotation is performed by the arms to position the wheels in contact on the support surface. (iii). Rapid upward symmetrical rotation is done by the arms to lift the leg off the support surface and produce a hopping motion. (iii). Antisymmetrical rotation is used to balance the frame at the leg.
A robotic system according to another aspect of the invention includes a body having two or more wheels that can be rotatably mounted on it and a motor for driving each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward, backward, climbing, hopping and throwing. The power source provides power for the drive motors, the system controller, and any or all of the sensors. The chassis consists of two drive wheels that are rotatably mounted on opposite ends of the body. Each drive wheel is positioned on an axle which is turned by a corresponding motor to rotate the drive wheel. An elongated pair of arms are mounted perpendicularly to the chassis on the opposite sides. Each arm has a proximal and distal ends that are mounted on the same axle. A second wheel is then mounted in the same plane as the corresponding drive wheels. Each arm is linked to a second motor. A linkage between each motor and the axle for each arms causes the second engine to rotate the chassis relative to the other. The distal or proximal ends of the arms can be balanced by independent activation of each motor. A joint with two degrees of freedom can include the linkage between each arm’s second motor and its axle, as well as the linkage between each drive motor and the wheel. Each arm can support a track in one embodiment.
“A robotic system according to another aspect of the invention includes a body with two or three wheels rotatably mounted on it and a motor for driving each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source provides power for the drive motors, the system controller, and any or all of the sensors. The body consists of a chassis with two drive wheels that are attached to each other and rotatably attached to a drive motor for rotating the wheel. An elongated pair of drive arms are mounted perpendicularly to the chassis on the opposite sides. Each drive arm has a proximal end that is attached to a corresponding axle and a distal one which supports a second drive wheel in a common plane. The boom arm is composed of a weighted section attached to connector arms. These connector arms are pivotably mounted on either side of the chassis so the weighted part is parallel to the chassis. A linkage connects the connector arms to at least one motor so that activation of at least one motor rotates the boom arm relative the chassis. The at least one motor can be activated independently to shift the center of gravity, allowing for balance on either the distal or proximal ends of the drive arms. The system controller controls both the drive motors as well as the at least one motor to shift the center of gravity reactively for stability. Each arm supports a track in one embodiment.
A robotic system according to another aspect of the invention includes a frame that has two or more wheels that can be rotatably mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The power source for powering the system controller, drive motors and one or more sensors is also included. Two or more wheels are made up of a plurality reaction wheels. The motor that drives each reaction wheel is housed within a housing. This housing contains a plurality momentum exchange elements, which are mounted on one or several axes attached at the frame. The frame has a geometrical structure that allows multiple momentum exchange elements to be distributed around the frame in order to generate angular momentum in different directions. One variation of the axes comprises a single gimbal-axis with a corresponding motor. Another variation is to have the axes consist of a single gimbal-axis with two corresponding motors. To protect the frame and momentum exchange components, a shell can be added.
“A robotic system is also described in another aspect of the invention. It includes a body that has two or more wheels mounted on it and a motor to drive each wheel independently. Based on the information received from one or more sensors, the system controller generates a signal to activate each motor. This feedback signal is used to provide reactive actuation of motors. The functions include forward motion, backward movement, climbing, jumping, balancing and throwing. The system controller, drive motors and one or more sensors are all powered by a power source. The body is a cylindrical with a rotational direction, with two ends. Each end defines a hub that aligns with the rotational axle for rotatably holding a wheel. A cavity in the body contains a volume for storage of objects having a specified diameter. The body is surrounded by an elongated arms that extend perpendicularly to the rotational direction. This allows a portion of the storage volume to communicate with the base portion. The elongated arm’s lower portion is located opposite the body and runs parallel to the plane that divides the cylinder. On each side of the bisecting plan, a curved channel is found. It has an exit end that communicates with the storage volume, and an entrance end that is defined by the hub and the inner surface of the wheel. Each channel is designed to receive the object and create frictional contact between its inner surface, the hub, and the lower portion of the body. This allows the wheel to draw the object into the channel. The motors can rotate the body relative to the wheels, so the elongated arms can be oriented horizontally. The elongated arm is oriented horizontally. Rapid activation of motors causes the wheels to turn in a first direction. This causes the body to revolve around the rotational axis in the opposite direction, accelerating the horizontal arm to a vertical position. As the elongated arms accelerate toward vertical position, an object placed on the base of the elongated arms rolls towards the distal end. The object will be thrown once it reaches the end of its arm.
“In the first exemplary embodiment, enhanced mobility in harsh environments, such as rough terrain or hazards, can be provided by a modified wheeled robot that combines a hopping capability with a leaning maneuver. This inventive robot has an end-over-end stair climbing ability. It raises its center mass above the obstacle and balances the vehicle on its toes. The drive wheels then shift their mass side-to-side for balance.
“The first embodiment of the robot consists of two independently driven wheels that are mounted on the ends and two independently driven arm assemblies. These pivot around a central leg to create either symmetric or anti-symmetric rotation depending on the desired motion. The arm assemblies can be adapted to travel linearly along the length the leg using a non-backdriveable motorized led screw. This linear motion allows for the vehicle to switch between an upright roving and toe-balancing configuration.
“The independently-actuated arms can function both as a hopping mechanism when rotated symmetrically about the central leg, and as an actively-controlled roll-axis stabilizer when rotated anti-symmetrically relative to the central leg. The robot can simultaneously stabilize and hop in its roll axis plane if the motions are properly superposed.
The multimodal robot of this invention is a better design than previous designs. It can leverage a highly efficient leaning maneuver and still have the hopping abilities to jump onto a platform or cross a gap.
“Applications for the multimodal robot of the first embodiment include reconnaissance in burning or chemical-contaminated environments, monitoring hazardous materials (e.g. “Providing mobile platforms for weapons and exploration of the planets, as well as for incorporation into toys, nuclear waste stockpiles.”
A second embodiment of a multimodal robotics system combines the ability to roll, balance and climb in a vehicle with treaded wheels or treads. This is done by shifting the vehicle’s center gravity relative its chassis. The vehicle can perform and stabilize ‘wheelies? You can also use?reverse wheelsies? Also known as’stoppies? An exemplary embodiment of the robot can overcome obstacles almost as high as its length (in its folded configuration). It does this by reconfiguring its center of gravity to overcome these obstacles. To carry sensors, cameras, payloads, or other electronic devices, a platform or frame should be connected to the chassis. Motors that drive the wheels or treads can be set up to rotate independently of the chassis. This allows the wheels or treads to be used for both rolling and balancing. This allows the robot dynamically adjust its center gravity. The robot can calculate its angle relative to gravity using MEMS accelerometers or gyroscopes. The robot can stand upright on its treaded toes by unfolding the tread assemblies. The robot can stand on its treaded?toes to expand the view from an onboard camera or other sensors and overcome obstacles that would otherwise prove impossible with a treaded robotic. This design can also cross chasms almost as large as the vehicle’s length and use the pivot on the chassis to dampen vibrations while driving over rough terrain quickly. You can choose from several modes of locomotion to adapt the robot for the terrain. This multimodal robot’s unique mechanical design and feedback control algorithms allow it to conquer complex terrain (e.g. Stairs, rubble), while maintaining a compact form factor to navigate in tight spaces and to lower cost and weight.
An actuated boom can be added to an alternative configuration for easier climbing and balancing. The boom is approximately the same mass as the chassis. The robot is equipped with motors to drive the wheels or treads and adjust the angle of the boom relative to the chassis. The robot’s configuration is detected by sensors, including one or more level sensors on each axis. These signals are sent to a controller. To allow the vehicle to balance on its treaded wheels or front toes, feedback may be used. You can also use the vehicle to climb over obstacles, including stairs. To do this, extend the boom’s mass over the obstacle and rotate the chassis upward and over. The maneuver can be performed in either a statically stable or dynamically balanced fashion. The boom arm can be extended and/or configured with its own wheels, treads, or both.”
“The robot’s center gravity can be shifted to allow it to overcome obstacles almost as high as its vehicle (in its folded configuration). This is done by repositioning the boom arm.
“This multimodal robot can be used for building, cave and mine exploration, search and rescue, monitoring hazardous materials (e.g. Nuclear waste stockpiles; detection and disposal of improvised explosive devices (IEDs); weapons platform; toys; planetary exploration; monitoring the HVAC system.
“In a third embodiment motion is provided in harsh operating environments and uneven terrain by a spherical robotic that incorporates momentum exchange to achieve rapid acceleration/deceleration in all directions.”
The inventive spherical robot is capable of traversing a variety terrains, including pavement, asphalt, gravel, gravel, and mud. It can also be equipped with an amphibious capability that allows it to travel through mud, swamp, or open water. The present invention is different from other spherical robots in that the internal frame is attached to the external sphere, while the center mass of the robot remains fixed at the center. For momentum exchange, single-gimbaled control moments gyroscopes are used in an exemplary embodiment. This design is extremely agile because the momentum required to maneuver is stored in the CMGs. It does not require the use of large-torque motors (and large electrical power-consuming) like a standard direct-drive system.
“In one embodiment, the cubical frame contains four single-gimbal CMGs with each gimbal angle at one face. As an alternative to single-gimbal CMGs you can incorporate a variety of momentum exchange devices, such as reaction wheels or dual-gimbal CMGs. Robots are not restricted to spheres as outer structures, but can also be used in generalized amorphous and ellipsoidal configurations.
The inventive spherical robotic robot is useful in military operations, such as covert reconnaissance and munitions delivery. Robots can also be used in general commercial applications as a toy, or as a therapeutic device.
“The fourth embodiment of the multimodal robot is a wirelessly-controlled or autonomous vehicle which is an all-in-one system of ball retrieval, storage and throwing. This design features an integrated ball pick-up mechanism and a jai alai throwing arm.
To enable ball pickup, the robot’s body and wheels are separated to allow for automatic picking up and loading of target balls. The robot is driven towards the target using this method. The robot’s curvature directs the ball into the spaces between the wheel of the body and the wheel. The wheel rotates the ball, bringing it up for storage in a basket or another storage container.
The feedback circuit stabilizes the robot to throw. It acts as an inverted pendulum and balances upright. Because of the great rotational inertia, the robot can quickly change from a lay-down to an upright position. This allows for the efficient tossing of light-weight balls. As the ball rolls off of the throwing arm track, it is spun. This results in a longer and more stable throw.
“The robot’s potential uses include remote-controlled toy cars, an automated tennis ball retrieval system and a grenade rocket launcher.
The following four multimodal robots are described. They include locomotion via tracks or wheels and spherical rotation. Also, they can hop, climb, throw, and do spherical rotation. Although different embodiments use different locomotion methods, one thing that unites them all is the use of feedback to control the angular momentum. This allows for active balancing and changes in the orientation and movement of robots. This makes them versatile and can be used for a variety of purposes, from toys and military applications to industrial applications.
“First Multimodal Robot Embodiment”
“Referring first to FIGS. The robot 10 in the first embodiment is shown in FIGS. 1-3 and 6. Two independently driven wheels 6 and 8 are mounted on the ends two independently driven arm assemblies 12 and 14 that pivot around central leg/shaft 16. By using a non-backdriveable motorized leadscrew 20, the arm assemblies 12, 14 move linearly along leg 16. The screw 20 provides a gradual motion that allows the vehicle to change between an upright roving and toe-balancing configurations (on toe 15 at the ends of leg 16. FIG. FIG. 2 shows the three rotational directions that the inventive robot moves around. Leg 16 corresponds to the yaw-axis and the axles of drive wheels correspond to the pitch-axis. Arm carrier 21 defines the midpoint in arm assembly and corresponds to the roll-axis.
Referring to FIG. 2. Arm assemblies 12, 14 are connected to a central arm carrier 21, via joints 11-13, which extend through the leg guide channels 48-49. An arm carrier 21 is driven along the leg 16 using a leadscrew powered via motors in the arm carrier. This allows joints 11 and 13 to be moved along the lengths the guide channels.
“Left Arm Assembly 12 includes a Parallelogram Linkage, which has basic?frame? Elements of a top right arm 22, bottom left arms 23, left arm link 30 and left-arm mid-link 25, respectively. Right arm assembly 14 also includes the frame elements of top right and bottom right arms 18, 19, left arm mid-link 50, right arm end links 47, and right arm arm mid-link 51. Preferably, the frame elements of arms are made from lightweight but very rigid metals such as titanium or aluminum. The frame elements can also be made from strong, rigid plastics or other polymers. Below are detailed descriptions of the joints and drive mechanisms which allow manipulation of basic frame elements.
The top left arm 22 is attached to the arm carrier via joint 11. It attaches via joint 31 to the left arm link 30 via joint 31. The left arm endlink 30 is connected to the bottom left arm via joint 32, and to arm carrier 21 via joint 13, respectively. The left arm midlink 24 attaches via joint 4 to the top left arms 22 and via joint 21 to the arm carrier 21 via joint 13. All joints are revolute joints in all cases.
“The left spring lever 25 attaches to the left arm assembly via joints33 and 34. As shown, joint 34 is offset horizontally from the middle of a line connecting joints 31-32. Attachment between spring lever 25 & joint 34 is made up of a standard revolute and joint 34 coaxial joint. Joint 34 can be attached to either a linear bearing that travels along the line connecting endpoints 25 of the spring lever 25, or to a straight-line?Watts? Linkage 70 is described in FIG. 1b, which includes the links 60,61, and 62 as well as connecting joints 36 to 37, 38, and 59. The arm assembly 12 won’t move if the 25-gauge spring attaches to joint 34 directly without any form of linear bearing/prismatic or straight-line linkage. The left spring lever 53 attaches to the right arm assembly through joints 55 and 56. This is in conjunction with a Watts linkage.
“The torque applied to the left chain drive sprocket41 at joint 32 causes left arm assembly 12 to be actuated. Sprocket 41 engages with the output shaft 29 (not shown) of the arm motor 27. It is located centrally within the left arm link 30. The right arm assembly 14 can be similarly actuated. Right chain drive sprocket 39 engages the output shaft (not illustrated) of right-arm motor 51. It is located within right arm end link 47.
Two extension springs, 5, 52 connect the arm assemblies. Left spring 52 connects to the proximal arm spring lever 25 at joint 35 with the right spring pretension pulley 54 (visible as FIG. 3.) of the right assembly. The right spring 5 extends from the right arm spring lever 53 to the left spring pretension pulley 26, in the same manner. The spring tension can be adjusted by turning the spring pretension pulleys 26, 56 in the desired direction. This adjustment is made by applying torque to the arm motors 28, 51, while their respective arm motor clutches 28,44 are disengaged. The arm motor output shaft 29, (right shaft not illustrated), has a limited range of travel. This will eventually cause the arm motor body to rotate, 28, 51. The spring pretension pulley 26 and 54 are then engaged via a single-stage spur transmission.
“FIG. “FIG.4” illustrates the possible modes of operation for the inventive robot. The robot can be operated using the independently-driven wheels 6, 8 and 20 as well as the leadscrew 20, independently actuated arms 12, 14 and leadscrew 20, which can each perform a variety of useful functions. Horizontal roving (a), is when the right and left drive wheels rotate in the same direction to tilt one leg forward. To move the vehicle forward, the wheels must continue to drive in the same direction as before. The end of the leg should be on the support surface. The wheels can be used in opposite directions to steer. The wheels can be operated independently, allowing the robot to turn quickly at a point or with very limited turning radius. FIG. 13 Horizontal roving Mode gives the vehicle a low profile that allows it to pass under low obstacles such as wires or fences. It also helps to avoid optical sensors that are placed several inches above the floor or support surfaces.
“An uprighting maneuver (b), which is a horizontal roving mode, involves applying a sudden and strong torque to the wheels in a specific direction. The vehicle experiences equal-and-opposite reaction torque when the reaction wheels are torqued in one way. A strong clockwise torque causes a counterclockwise rotation of your leg to move it into a vertical position. Reaction control thrusters or simply by bringing the vehicle back into contact with the support surface can be used to blot off the motion of the reaction wheels. Reaction wheels only provide instantaneous torque, and this is limited by the motor that drives them. The robot is only able to drive in the upright mode using the reaction wheels. With the leg pointed up, it provides a support frame to mount vision systems and other sensors.
Reaction-wheel stabilization can be used for upright balancing and roving in the fore-aft orientation (c), toe-balancing, hopping (d), and toe-balancing. Reaction wheels can be used in the left-right direction as counterweights (similar to a tightrope walker?s balance bar). The reaction wheels can also be used as counterweights to the stiff elastomer Spring to prevent the vehicle from hopping in conventional monopedal locomotion or cartwheeling monopedal loomotion (f), (g).
“The wheels must have a significant mass to enable the three last functions (e,f and g), to work. The vehicle batteries 7 provide the mass for each wheel in the exemplary embodiment. They are distributed symmetrically around each wheel’s outer hub and the motors 45 within their respective motor housings 9. These motors drive the wheels 6 through 8. The robot’s overall weight can be reduced by utilizing the relatively heavy components rather than adding weight to the wheels.
“The independently-actuated arms 12, 14 can function both as a hopping mechanism when rotated symmetrically about the central leg 16 (around the roll-axis) and as an actively-controlled roll-axis stabilizer when rotated anti-symmetrically about the central leg. FIG. 5a shows a hopping motion. In FIG. 5a, a hopping motion is made by starting with an arm arrangement that has the arms angled downwards (indicated in FIG. 5a – Slowly rotating the arms 12, 14, symmetrically upward relative the leg 16, and abruptly halting when they reach horizontal orientation. A few level sensors (not illustrated), may be found on the leg 16 and/or the arm assemblies 12, 14, to generate electrical signals which are sent to the vehicle’s control unit (not shown). The controller could be integrated in one or more commercial and/or off-the-shelf (COTS) printed circuit board (PCBs) as an example. This includes the Texas Instruments C200 MCU. The protective housing should be attached to the leg 16 so that it does not affect the operation of the leadscrew. The level sensors can provide feedback to help control the antisymmetric arm motion to balance. FIG. FIG. 5b shows that anti-symmetric arm motion generates a similar and opposite torque around the leg 16 which allows feedback stabilization around the roll-axis. The robot can simultaneously stabilize and hop in roll-axis plane if these two motions are properly superposed. To allow the arms to hop and balance the vehicle effectively, the majority of its mass should be concentrated at their ends.
“The preferred embodiment’s leg 16 should be made from a lightweight material with sufficient stiffness to prevent buckling and allow for structural flexibility. Aluminum, titanium and lightweight steel are some examples of suitable materials.
The wheels 6, 8 provide pitch-axis stability when out of contact with the ground. They do this by actively applying torque using the same principle that the arms. Parallelogram linkage is used to ensure that the arm assemblies 12, 14 have an angular alignment of 6/8 relative to 16 at all times. This reduces coupling between the pitch and roll-axis dynamics, simplifying the overall dynamics. To prevent interference between coplanar elements, the top and bottom arms 18, 22, and 19, 23 respectively should have an outward curve at their lengthwise centres, as shown in this diagram. The arm sections’ ends curve inwardly relative to their midpoints. For small angular deflections (+/?15, the wheels could be attached directly to one link.
“In the preferred embodiment, the left and right arm motors 28, 51 are high-speed/low-torque in order to optimize hopping performance. To support the weight of both the arms and recover energy while hopping, the arms are spring-loaded with extension springs 5 52. This spring mechanism must resist movement of one arm relative the other to support the weight of wheels during hopping. However, it shouldn’t substantially resist rotation of either the central leg or arm. This arrangement permits the active roll-axis stabilization to be achieved by allowing for anti-symmetric rotation.
While a torsion-spring across the arms meets these basic requirements, more functionality can be achieved through a more complex linkage mechanism. Specifically, since each arm is actuated by torque applied at one of the outward joints by the corresponding high-speed/low-torque motor 28, 51, a digressive stiffness (decreasing with increasing deflection) is desirable in order to provide a more constant resistance to symmetric motion; i.e., provide high support at small deflections, without overwhelming the motors at large deflections. To facilitate multimodal operation, it is preferable that the spring rate can be adjusted on-the-fly without creating torsional bias/asymmetry. The arms should be able to self-lock to a fully-tensioned position without additional actuators in order to store energy during large jumps and to prevent the vehicle from being folded during roving. To prevent collisions between coplanar mechanism link links, the angle at which locking takes place must be less that 90 degrees.
“The preferred embodiment incorporates a pair non-coplanar springs 5, 52 that are attached to spring levers 25, 53 in the parallelogram linkage. This creates a self-locking feature. FIG. 7 illustrates the relationship between springs 5, 52, and levers 25, 53. FIG. 7 shows the relationship between the springs 5, 52 and levers 25, 53. The FIG. 7 diagram shows the top plane. 7 includes right spring 5, left Spring lever 25, and joint 34′, which includes joint 34 & Watts linkage 70. The bottom plane is shown in the middle of the figure and includes left spring 52 and right spring lever 53. It also includes the joint corresponding left joint 34? which includes joint 55 with its Watts linkage (or another appropriate linkage). The respective joints are identified in FIGS. 1-3. FIG. FIG. 8. illustrates the kinematic equivalent realizations for the arm suspension mechanism in FIG. 7.”
“As shown by FIG. 9 shows that the resistance to symmetrical motion decreases with increasing horizontal deflection (arms outstretched as in FIG. 1), which is measured as the angular displacement (??L=?). 1), measured as angular displacement (?L=?). Eventually, the sign changes sign beyond a certain critical angle. In the plots. The arms lock into a fully-tensioned state, provided the arms are not allowed to deflect beyond this critical zero-torque angle. FIG. 9 shows the relationship between angular displacement and percentage spring stretch, resultant torque (in Newton meter) and effective torsional spring rate (in Newton meter/radian), respectively. FIG. 9 shows the angular displacement relative to percentage spring stretch, resultant torque (in Newton meters) and effective torsional rate (in Newton meters/radians) at four levels of spring pretension. FIG. FIG. 10. This shows the resistance to antisymmetric rotation under different levels of spring pretension. It uses the same comparisons as FIG. 9. FIG. FIG. 11. This plot shows the critical zero-torque angle (locking) as a function varying link lengths forsymmetric rotation. B/L=0.125; C/L=1.094; and D/L=0.438.
“Note: The symmetric configuration allows bi-directional series elastic actuation with the extension spring. Referring to FIG. Referring to FIG. 12, the left arm motor 28’s main body is kept stationary by a small, actuated clamp 62 during normal operation. The motor 28’s body can rotate by loosening clamp 62. This allows the left spring pretension pulley 27 to rotate around the one end. To adjust the tension on the spring 5, right arm motor 51 can be turned by loosening the clamp that is not visible in the figures. These features allow springs to be pre-tensioned, while the arms 12, 14, are locked at their maximum travel. To do this, loosen the clamps 62 and drive the motors 28, 51 in the opposite direction to cause downward arm motion (to prevent unlocking). The springs 5, 25, are always under tension. You can tighten them by driving the pulley 27, 54 in either of the directions. The motors 28, 51 can also be actuated in series with the springs 5, 25, by loosening their clamps. This is often called a “series elastic actuation”. This may be used to buffer mechanical energy and protect motors 28 and 51 from mechanical shock.”
“As mentioned above, each drive wheels 6, 8 have two motors that propel and steer the vehicle (via differential drive), when it comes in contact with the support surface. Referring to FIGS. Referring to FIGS. Drive gears 45 and 45 engage spur gear 40 which is mounted on axle 46. The batteries 7, which provide additional weight for monopedal, hopping, and balance, are mounted on each wheel hub. Drive wheel 6 is on the left with two motors 45 and spur gear 42. These drive the wheel around the corresponding axis.
“In another embodiment, the drive wheels can be replaced with a second set or arms that are mounted in an orthogonal configuration with the arm assemblies 12. This creates a pair of pitch-axis arms and a pair of roll-axis arms. To provide feedback on anti-symmetric arm motion, level sensors can be installed within the pitch- or roll-axes. This structure can allow for monopedal locomotion with high stability that can be balanced in multiple axes. To provide the required mass for hop and toe balance, the weights of the drive motors and wheels are eliminated from this design.
The multimodal robot can be equipped with audio, thermal, chemical, and optical sensors. A transceiver can be added to the electronics of the vehicle for remote commands and information transmission.
The robotic system described in this article is capable of maneuvering in complex structures and rugged terrain using a variety of combinations of hopping. Pole climbing, toe balancing, horizontal walking, uprighting, and pole climbing. All done in a controlled manner. The robotic system can be used to climb stairs by using toe balancing and pole climbing.
“Second Multimodal Robot Embodiment”
FIGS. A treaded vehicle can perform stable heel and toe standing (i.e., ‘wheelies?). able to balance on the edge or similar elevation change. FIG. 14a The multimodal robot 100 comprises a pair 110 and 120 of arms that each have their own tread assemblies. They are attached to chassis 101 via tread shaft 108. The exemplary embodiment contains all the electronics and batteries needed for operation and communication. Rotation of the shaft108 causes the tread links 108 to move for translational movement. Rotation around the shaft causes the whole tread assembly to turn with respect to its chassis. This unique “hip joint” is described below. Below is a detailed description of this unique?hip joint? Optional platform 104 can be attached to chassis 101 to allow for attachment of sensors, cameras or other equipment to the robot. A housing can be used to protect the chassis, any electronics, batteries, or actuators, where there is no platform. If platform 104 is present, the chassis housing may be one structure. In this illustration, chassis 102 is separated by a dashed line. The chassis housing can also be enclosed within the platform. Platform 104 does not have to be rigid. It can be either a rigid or deformable structure that can be passively or active deformed to allow the robot to be used for specific tasks. The platform does not have to be enclosed. It can be open or combination of open and closed sections.
“One or more sprockets can be driven by an actuator, such as a motor or engine, pneumatic turbine, or motor. FIG. FIG. 14b is a simplified diagram that shows the components of a tread-assembly with the side cover removed. Each tread assembly contains two or more treadsprockets (114, 116) that are rotatably mounted on a vertical sideplate or frame 111 in order to engage tread 112. Frame 111 may also have one or more tread guides. Tread sprocket114 is coaxially mounted with shaft 108. Mounting a sensor to measure speed, position, or torque may be possible for either sprocket 114 or both. Optionally, a force sensor or pressure sensor can be mounted underneath the tread 112 in order to determine where the tread assembly contacts the ground or another surface. You can also include mechanisms that adjust the tension of your tread, as is known to the art. Control electronics, batteries and communications electronics can be installed within the tread arm 110 or within chassis 102, platform 104, depending on the situation.
“Referring briefly at FIGS. 20b and 20c, wheels 124 can be mounted rotatably near the edge of platform104, opposite to the chassis, in order to expand the robot’s functionality. FIG. FIG. 21a shows the robot maneuvering in a narrow passageway, such as a duct 128. The robot effectively binds itself between the sides of the tunnel. The robot can apply pressure perpendicularly to the duct side using the wheels 124 as it moves along the length of duct. To provide feedback to the robot’s controller, sensors within the treads and attached to the tread shaft can be included. This will allow it to adjust the relative angles between the chassis/treads in order to maintain the required pressure to allow it to move through the passageway or duct. For additional control, the wheels 124 can be attached to allow them to freely turn around their axles or may be attached directly to the shaft of one or more motors.
“A variation of FIG. FIG. 14a illustrates a variation on the embodiment of FIG. 17 where the tread assemblies have been replaced by a corresponding wheel arrangement, which comprises two or more wheels, 117, 118, that are rotatably mounted in planar relation on the arms 119. Toe balancing, or other maneuvers that require force to apply at the distal or tip of the arm 119 can be performed in this embodiment. Axle108 extends from chassis 101 as described above to drive wheels 120. These are the details of the robot’s “hip joint?” The maneuvers and movements that can be achieved by this joint are equally applicable to FIG. 14a and FIG. 17.”
“Referring FIG. “Referring to FIG. 19, in the preferred embodiment of FIG. 19, a two-degree of freedom joint is used in a mobile robot. 14a connects each arm 110, 120, or 119 in the wheeled model to the chassis. It transmits two coaxial torques, but they are decoupled. To transmit the torque needed to rotate the wheels 112, 122, the tread shaft 108 is connected to the motor 140 at one end via coupling 138 and the other end to the drive sprocket (or wheel). The shaft is able to pass through the tread gear 130 which is fixedly attached to the arms 110 to 120 (or 119). The pinion gear 130 is mounted to a second shaft 136, parallel to the tread shaft 110. This causes the pinion and arms 110, 120 (or 119) to rotate relative to the chassis 102. It can be driven by coupling 138 by the second motor 142, also known as the boom motor. As will be explained below, this assembly allows for adjustment of the center-of-gravity. The slip ring 144, which may have one or more channels, can be coaxially located with the first shaft. It transmits and receives power and/or electric signals between the chassis and arms 110 (or 120) during a continuous range in rotation. To provide feedback to the control system, optical encoders 134 can be used to measure the angle between the chassis and arms 110, 120 (or 119) to determine the angle. Alternately, all components of the hip joint (i.e. motors, gears, and sensors) may be located within the arms. In this case, the chassis could be simply an axle that connects the shafts 110, 120, or 119 together.
“The embodiments shown in FIG. “The embodiments of FIG. 14 and FIG. This allows the robot dynamically adjust its center gravity. Commercially-available MEMS accelerometers and gyroscopes, coupled with advanced filtering techniques, allow the robot to estimate its angle with respect to gravity. The multimodal robot, illustrated in FIGS. 110 and 120, can be balanced upright with the arms 110 and 120 extended from the body (with respect to tread shaft 108) as shown in FIGS. 15b and 20c allow for a significant increase in the range of an instrument or sensor on board, such as a camera. A robot with tread assemblies measuring between 10-15 cm and 30-50cm in height may be capable of standing up to 65cm tall and overcoming obstacles that would otherwise prove impossible with a robot only 10-15 cm tall. This inventive design can also be used to cross chasms almost as large as the vehicle’s by moving the arms in opposite directions. 15c and 20b The front-mounted pivot on the chassis can be used to dampen vibrations while driving over rough terrain quickly. Because the arms can be reconfigured, there are many modes of locomotion that the robot can choose from depending on the terrain. FIG. FIG. 15a and FIG. 20d show how the robot can balance on the proximal (with respect to tread shaft 108) end of its arms. FIG. 15a and FIG. 20d, the robot can balance on its proximal (with regard to the tread shaft 108) arm end. This means that the robot can perform a wheelie with the proximal 110, 120 end in contact with ground, but neither the chassis 102 or the distal end the arms in contact. This is known as the “V-mode”. You can change the angle between chassis 102, arms 110, 120 by activating the boom motor. The tread motor will then be actuated as necessary to maintain the changing center of gravity above the contact point. This will prevent the robot from falling to the ground. The robot may change the angle in response to a reference command, or it could be performed by an operator. This maneuver can be used, for instance, to start a climbing sequence. FIGS. FIGS. 15b and 20c show the robot in a toe-balancing mode, also known as a?stoppie?. This is achieved by placing the distal ends of the arms 110 and 120 in contact the ground, but neither the chassis 102 or the proximal end of the arms are in contact the ground. This is known as the “C-balancing mode”. You can change the angle between chassis 102, arms 110, 120 by activating the boom motor. The tread motor will then be actuated as necessary to maintain the contact point’s changing center of gravity. The robot may change the angle as a result of an operator’s reference command, or it could be performed automatically in response to an external stimulus. The robot can use multiple locomotion modes according to an inventive mechanical design and feedback control algorithms to get around obstacles such as stairs and rubble. However, the robot is small enough to maneuver in tight spaces and save weight and cost. A preferred embodiment of the electronics on board includes wireless communication circuitry as it is known in the art to enable bidirectional communication via WiFi. A preferred embodiment includes the appropriate electronics and programming that enable the robot communicate with other computers, robots and mobile devices using the IEEE 802.11g standard.
FIG. 2 illustrates some of the complex tasks that can easily be accomplished by a treaded/wheeled robotic robot. FIG. 21a, which was previously discussed, and FIG. FIG. 21a, which was discussed above, and FIG. Small surfaces such as a stair edge (126), a branch or a telephone line or power line, are ideal. The robot’s treads are in contact at one point with the surface. The robot adjusts the boom and chassis to maintain its center of gravity and keep it in line with that point. To determine the contact point, inertial sensors, such as accelerometers or gyroscopes, may be combined with contact sensors (e.g. force sensitive resistors) within the tread assemblies. The combination of the tread motors and the balancing motors, as well as continuous feedback from sensors to control them, provides active balancing to stabilize the robot’s position. When the robot climbs up or down stairs, the center of gravity shifts in the desired direction. 126 This is done so that the contact point is directly above the robot’s center of gravity using a variety of movements.
“FIGS. 22a and 22b are two examples of the operations that can be performed by the multimodal robot described above for climbing obstacles such as stairs. Step 160 is where the robot approaches the step and balances on the distal end (in?C?balancing). FIGS. 15b and 20c respectively. Steps 162 and164 are where the chassis position is adjusted upon reaching the step so that the center mass is directly above or below the edge of first step. The robot balances on the edge and gradually moves up the step using a combination of tread actuation, appropriate angle variation between the treads, and chassis adjustment.
“In one embodiment of this maneuver, the angle between treads and chassis is actuated using a function time. This is to maintain the center of mass above the edge of step and maintain the desired angle between chassis and horizontal. The contact point between treads, the edge and treads moves (relatively slowly) along an arm. Balance is then achieved by feedback control via tread actuation. Feedback control is used in a second version of the maneuver. This involves a combination of tread actuation as well as small adjustments to the angle between treads and chassis.
There are two possibilities when the vehicle reaches the top of a step. The first is that the angle between the edges of successive steps and the angle of horizontal of the chassis is greater than the angle of horizontal of the chassis (that is, the angle at which the steps are relatively narrow). The vehicle will continue forward motion in either case, returning to C-balancing mode after reaching the top. The situation will be the same if it reaches another step.
The second scenario is where the vehicle does not reach the top of the stairs and the angle of successive steps is relatively low. The angle of the chassis as it approaches the top of the current step from horizontal may be almost the same angle as the angles of the edges from the next steps from horizontal. This will allow the vehicle’s proximal end to reach the edge at the next step without contacting the edge of step 8. You can adjust the center of mass to reach the edge of the next steps (9) or (10). The process described in steps (4) through (7 are repeated as illustrated in steps (11) and (15).
You can use the following steps to move the robot in the desired position for a task. This and other similar tasks are possible because the robot can operate, or can be operated to, shift its center gravity to balance on a small point. It does this by changing the angle between the chassis and the arms, and using the treads and wheels to?catch’ itself. Before it falls.”
The multi-modal robot in the second embodiment can perform a variety of maneuvers using a minimal number of actuators. This saves cost and weight. You can mount additional sensors internally or externally. These include contaminant sensors and Global Positioning System (GPS), receivers, wind sensors. Analog or digital cameras, optical, radiation, or optical sensors. Mobile robot platforms 104 and arms 110, 120, and 119 can be equipped with end effectors. These include linkage mechanisms that have a gripper, liquid or solid collection systems, lighting systems, weapons systems, and other devices.
FIGS. 16a-c . This configuration still allows for shifting of the center gravity, but the method of shifting is different.
“In this embodiment, the robot is equipped with a chassis 148 as well as an actuated boom 150. The chassis 148 is driven using a pair of treads (152, 154) or conventional wheels (156), as shown in FIG. 18). The 150-pound boom has significant mass. The boom’s mass is roughly equal to that of the chassis in the exemplary embodiment. The robot is equipped with motors to drive the treads or wheels and adjust the angle of the boom 150 in relation to the chassis 148.
“The hip joint as described above, with reference to FIG. 19. may be added to the configuration that uses a boom to shift the center of gravity. The boom motor, which corresponds to the balance motor, will turn the boom arm.
“The second multimodal robot embodiment has sensors that detect the robot’s configuration. The vehicle can balance on its front and rear cogs or wheels by applying feedback control. You can also use the vehicle to climb over obstacles, including stairs. To do this, extend the mass of 150 pounds over the obstacle and rotate the chassis upwards and back. The maneuver can be performed in either a statically stable or dynamically balanced way. The boom arm can be extended and/or configured with wheels or treads in a similar fashion to the wheels 126 in previous configurations.
“As with the first multimodal robot, the configuration with the Boom 150 takes advantage the weight of the battery to be used as a functional mass. To transmit power from the batteries to motors within the chassis, an electrical connection is created between the boom and chassis. This connection is made using slip rings, which are steel shafts mounted in bronze bushings. The boom can be rotated around the chassis without restriction by the slip rings.
“In this configuration the robot’s treads are in contact at one point with the surface. The robot then maintains its balance by moving the boom so that its center of gravity is in line with the contact point. Inertial sensors (e.g. Contact sensors, such as accelerometers or gyroscopes, can be used together with them (e.g. To determine the contact point, force sensitive resistors are placed inside the tread assemblies.
“The second multimodal robot design uses multiple commercial off the shelf (COTS) sensors, including MEMS-based accelerometers (and gyroscopes) and optical encoders (134 (shown at FIG. 19) To estimate the angle between the chassis and gravity (in FIG. 14) and the angle between the boom arm and the chassis (in FIG. 16). Programming the robot involves a control system, which may include a Kalman filter, to activate the motors to balance it dynamically. The prototype accepts manual input via the COTS radio frequency remote.
“In one application, the second multimodal robot embodiment was used to create an ‘army? One application of the second multimodal robot embodiment was to deploy the robots in an open area (a parking lot), where plumes of colored smoke were released. Each robot was outfitted with electronics and a sensor pack to measure smoke concentrations. These measurements were sent in real-time (via WiFi or 3G cellular data connections) to an off-site supercomputer that ran advanced weather-forecasting algorithms. These algorithms then synchronized a numerical simulation (or smoke plume) with actual field measurements in real-time (a problem called data assimilation). Then, the vehicles were told where to go next to reduce uncertainty in the forecast. The system was successful in achieving its goal. It was able to predict where the smoke would go and coordinate the vehicles to gather the best information for each wind condition. The research has important social relevance related to new technology and algorithms for tracking a wide variety of environmental plumes of interest, from gulf-coast oil, to Icelandic volcanic ash, to possible chemical/radioactive/biological plumes in homeland security settings.”
“Third Multimodal Robot Embodiment”
“In a third embodiment, the spherical robot incorporates momentum exchanging devices to achieve rapid acceleration and deceleration in all directions.”
“As illustrated at FIG. 23 illustrates an example embodiment of the spherical robotic robot according to the invention. A frame 202 supports a plurality momentum-exchange element 204 so that they are distributed relative to a surface of a sphericalshell 210. The frame 202, elements, 204 and all electronics, actuators, and batteries required to power and control it. To optimize balance and locomotion in different environments, sensors may be added. Wireless communication devices may be included in the control electronics to allow communication with a remote computer or mobile phone. The spherical robot can also be tied to a controller such as a joystick or track ball, or any other external control device.
FIG. 2 shows the basic elements of three momentum exchange elements that could be used in the SPHERICAL ROBOT. 24a-24c . FIG. 24a contains a single motor to spin the wheel. FIG. 24b . This assembly contains two motors. One for spinning the wheel and the other for rotating the gimbal. This allows for a variety of angular momentum. FIG. FIG. 24c shows a double-gimbal control moment (DGCMG), with three motors including two motors used in the SGCMG and a third to adjust the plane on which it sits.
“In FIGS. FIGS. 23 and 26 show the configuration of the fourth embodiment. To achieve the desired function, the SGCMGs can be operated separately or together. Frame 202 is shown as a cubical shape, but it can be made with any geometric shape that fits within the spherical shell. This includes conical, pyramidal, symmetrical, skewed and linear arrangements with 3-D structures. FIG. FIG. 25 shows a few examples of the many possible combinations of momentum exchange elements. These include a pyramid and skewed cone as well as a symmetrical octahedron and roof-types with linear combinations. Any geometrical shape that allows momentum to be generated can be used. This includes a variety of directions that allow for steering, rolling and balancing. The robot’s outer structure is not limited only to spheres, but can also include generalized amorphous and ellipsoidal configurations.
“FIG. “FIG. 26” shows a three-dimensional illustration of an exemplary implementation for the inventive spherical robotic system. The frame 202 should fit snugly within the spherical 210 shell, as illustrated. If the cubic frame is used, the corners may be chamfered as shown to give the shell 210 a wider, more rounded surface that contacts the frame. This ensures that the shell 210 has a uniform structural support and that the frame 202 as well as the components that are mounted on it are stable supported.
“As illustrated in FIG. 2, each SGCMG204 a-d contains the spin motor. (The shaft of the spinmotor 220 can also be seen in FIG. 26), and reaction wheel in a small cylindrical housing. The spin motor can be seen in FIG. Each gimbal-axis has a shaft attached to it. The other end is supported by a pivot, so that the reaction wheel and axis rotate when they are driven by the respective gimbal motors.
All electronic components necessary for operating, communicating with, or collecting data will be contained within shell 210. It is best to center the frame 210 so that the weight is at the center. These components may include one or several printed circuit boards, as well as battery casings, or other holders. The components may be supported on a plate or bar that extends between the corners of the cube, or between the upper and lower faces 208 e of the cube, as illustrated. This will not interfere with the movement of elements 204. If the frame is hollow, some components, such as the batteries, can be mounted inside the frames’ edges. Alternative embodiments of elements 204 can be mounted on all six faces of the cube or on any face of a chosen geometric structure as long as there is enough space to prevent interference with movement of momentum exchange elements.
“FIGS. 27a and 27b show an alternative construction of spherical robotic with the outer shell removed. The intersection of four open-centered discs 234a-d, which correspond to faces 208a-d in FIGS, creates frame 232. 23 and 26. Additional structural support is provided by the sphericalshell’s rounded faces. Attached to the top of frame 236, is the top housing 236, which houses the control electronics.
Referring to FIG. “Referring to FIG. 27b, which shows an exploded image of the complete assembly with one SGCMG, also in exploded views, the frame is defined as the assembly of faces 234 a-234d with top plate 244 e bottom plate 245, which are attached using brackets 242. A number of battery holders 240 are attached to the top surface of top plate 244 to hold the 238 retaining batteries. The batteries are button-style lithium batteries. Additional battery holders 240, 238 and 238 can be found on the outer surface 245 together with the gimbal motor controllers 244.
“FIG. FIG. 27c is an exploded view showing SGCMG250. 27b . Attached to the shaft 270 is the rotor 268. The rotor is responsible for providing the inertia necessary to store momentum of a SGCMG. The outer housing is formed from 256, 259 and 260, 260 and 267, 267 and 272, and held them in place by the rotor and the rotor shaft 268, 272. They are also held in place by the journal 252, 277, thrust bearing 258, 271, and combination of 258, 272. Attached to the shaft of the spinmotor 254 is the rotor shaft 275. The spin motor 254 attaches to the cring 252, which is attached to bottom plate 256. The spin motor 254 rotates rotor 268 at the same rate as the SGCMG or VSSGCMG cases. This is done via feedback from the optical encoder 282 and spin motor electronics 282. The optical encoder 280 attached to the top plate 276 is used to measure the rotor speed. Mounting posts 279 are used to mount the spin control electronics 282, which are attached to the top plate 276. Attached to the housing assemblies 256, 259 and 260 are the gimbal shafts 268, 267, 276, 278. Attached to gimbal shaft 269, a spur gear 262, with a thrust/journal bearing combination, is a one-gimbal shaft. The spur gear 262 is kinematically bound to a second spur drive 263 that is attached to gimbal motor 261; it is also free to turn relative to right gimbal mounting bracket. The slip ring assembly 274 holds the second gimbal shaft 273. It is rigidly attached to it and can rotate relative to the left-gimbal mounting bracket 266, via a thrust/journal bearing combo. Despite the continuous rotation of gimbal, the slip ring assembly 274 supplies power to the spin motor controller 282 A potentiometer 273 measures the angle of rotation of the gimbal shaft 273. It attaches to the gimbal shaft while the immovable part attaches to the left gimbal mounting bracket (28) Attached to the sidewall 234 are the right 276 and left 264 gimbal brackets.
“In one embodiment, the robot may be equipped with pressure bladders that are attached to the shell 210’s inner surface or at non-interfering places on the frame 202. FIG. 23 shows an illustration of a single pressure bladder (214). 23). 23. The momentum exchange elements allow the buoyant robot, which spins as it moves, to travel within or above the water’s surface. This makes it an amphibious vehicle. One implementation allows the bladders to be filled to the desired buoyancy before the robot is deployed via a valve through the shell. Another approach is to mount small, compressed gas canisters on the frame. These can be used in buoyancy compensators and life vests. A feedback system will communicate with the frame to determine the conditions of the body of water. The system will control the gas release into the bladders in order to achieve the desired buoyancy. This will allow the robot to maneuver efficiently and effectively. The bladders can also have bleed valves that allow for active adjustment of buoyancy in response to changing conditions. After a few uses, the gas canisters can be replaced with new ones.
The robot can also be made passively buoyant by selecting the right material. The frame can be made from lightweight materials such as plastic, wood, fiberglass or titanium, depending on its strength and durability. You can use hollow or partial-hollow materials for the frame, such as honeycomb structures, extruded channels, or honeycomb structures. A shell could be made from either a buoyant polymer or buoyant plastic, such as neoprene, polystyrene or closed-cell foam. It should have a continuous surface that is watertight. For applications that require metal, the buoyant foam structure can be covered with an impervious or coated outer skin, such as a lightweight metal or epoxy resin. This construction is similar to what you see on surfboards. To seal the openings (ports and doors) in the shell that allow access to the interior components of robot, it would be necessary to make sure they are watertight.
“FIG. “FIG. 28” shows a block diagram showing an exemplary control structure that can be used in conjunction with the spherical robotic arm. Other control architectures are possible, as will be obvious to those skilled in the art. You can achieve the path generation block by determining the relationship between the velocity and the angular rates. The ACS control block, pseudoinverse CMG steering block and gimbal angular rates controller block can all be derived using methods and algorithms that have been developed in the art.
“Locomotion in a liquid body can be achieved by activating momentum exchange elements to turn the robot’s body in the desired direction, just like on land. FIGS. FIGS. 29a-c show different uses of the spherical robotic arm. FIGS. 29a and 29b show a free-surface and near-a-surface cases, respectively. FIG. FIG. 29a shows that in fluids, the RWA spins counterclockwise, and the sphere rotates clockwise. The fluid’s interaction with the rotating sphere causes the sphere move in translation to its left. This is determined by the Navier-Stokes equations. These equations show that a rotating circle in an incompressible viscous liquid near a wall or free surface can move in a translational orientation orthogonal to the fluid’s angular rate, and parallel to the wall. See. J. Happel, and H. Brenner, Hydrodynamics with Low Reynolds Numbers: With Special Applications to Particulate Media, Springer 1983. This reference is incorporated herein. FIG. FIG. 29b, which is movement on top of a substrate, shows that when the RWA spins in one direction (clockwise) the sphere spins counter-clockwise (counterclockwise) propelling it to the left.
“A plurality spherical robotics can be used in conjunction to enable locomotion and overcome various obstacles. FIG. FIG. 29c shows a series of steps for stacking several spherical robotics in order to raise one or more of them. This gives the robot(s), at the top, an enhanced view to collect visual information and/or perform other tasks that might require overcoming obstacles. Three spherical robots (designated as A,B, and C) are placed side-by-side on a support. To squeeze robot B up in step 2, robots A and B move towards each other. Step 3: A and C are joined with B balanced on top. Step 4 adds robots D, and E to the mix. C and E are moved towards each other to push D upward. To keep B on top, A will move with C. After C and E have joined, step 5 sees B and D on top. F is forced upward by F when F’s spherical robots F, G, and E. In step 6, F, D, and D are joined on top of E, A, C and E. In step 7, D, D, and F move towards each other to push D upward. Step 8: D moves to the right and climbs up on F, while B moves to the left. Step 9 shows how the multiple momentum exchange components of each robot allow D to balance on top F, which then balances on top E. The spherical robots can be stacked to position a robot equipped with a camera or another sensor to view over obstacles. The spherical robot can approach obstacles with a low profile and still be able to work with similar robots.
“In an example application, multiple spherical robotics can be deployed with each robot carrying a different payload or instrument. Robots deployed together can work in concert to allow the robot carrying an instrument to be at its best position to complete its task. The above-described spherical robotic can be used for covert reconnaissance and munitions delivery in military and law enforcement applications. The robot can be used commercially as a toy, or therapeutic device.
“Fourth Multimodal Robot Embodiment”
“FIGS. 30-36 illustrate a fourth embodiment of the multimodal robot, which is a wirelessly-controlled vehicle that can perform the tasks of object retrieval, storage and throwing. This design features an integrated ball picking mechanism and a throwing arms. The fourth embodiment, although it is described as a ball-handling robotic, can be used to pick up and throw any other objects that are sufficiently symmetrical to enable the pick-up mechanism. The throwing arm, which is described as “jai alai” in the example, can be modified to take different shapes depending upon the speed, trajectory, and spin of the object being thrown.
The robot’s body and wheels are designed to automatically pick up and load target balls. This feature allows the operator of the robot to steer it towards the target by using the curvature and rotation of the wheels. The wheel rotates the ball, allowing it to be placed in a basket or another storage container.
“To throw, the robot is stabilized using a feedback control circuit. It can balance upright like an inverted pendulum. Rotational inertia generated by the motors driving the wheels allows the robot’s body to be rotated quickly from a laid-down to an upright position. This allows for the efficient tossing of a lightweight ball. The unique shape of the throwing arms gives the ball a spin as it rolls off the track. This results in a longer throw and more stability.
“As illustrated at FIGS. “As illustrated in FIGS. 30 and 31, the fourth robot embodiment 300 has a molded body 302 which is roughly cylindrical (circular when viewed from the side), with a diameter (between the wheels), and a width (between them) of approximately three times that of the target object. The pingpong ball is the target object in the exemplary embodiment. It has a diameter around 40mm. Two coaxial wheels 306 can be mounted on a rotational axle 303. Each wheel 306 can be driven independently by a motor (not illustrated). This motor is responsive to active feedback controls that provide the robot with a selfbalancing function. The control electronics that receive feedback and activate the motors are housed on a printed circuitboard (not shown), which is covered by a removable cover 309. A number of batteries, not shown, are located in the lower part of body 302, just below the rotational direction 303. They can also be accessed through the back cover 303. The robot’s center of gravity is located above the rotational direction so that the motors and electronics are not switched off, it will fall over.
The vertical arm 304 can be used as a track to launch the object and as a mass that allows for backward and forward movements through leaning. The track in the exemplary embodiment has a curvature similar to that of a jai alai Cesta (basket). To restore vertical balance, the robot moves forward when it leans forward. The wheels are rotated in opposite directions to facilitate turning.
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