Metaverse – Necip Berme, David James Oravec, Aysun Gokoglu, Bertec Corp
Abstract for “Force measurement system”
“A force measurement device is described in this invention. The force measurement system comprises a force measuring assembly that can receive a subject, a visual display screen and one or more data processing units that are operatively coupled with the force measurement apparatus and the visual display. The force measurement assembly can be a static force plate, and the visual device can be a head-mounted or an output screen that is configured to at most partially circumscribe the three sides of the subject’s torso. The force measurement assembly can be a displaceable forceplate and the visual device is a head mounted visual display device.
Background for “Force measurement system”
“1. “1.
“The invention generally refers to a force measurement device. The invention is more specifically related to a force measurement system and a method of testing subjects using that system.
“2. Background”
“Force measurement systems can be used in many fields to measure the reaction forces and moments between a body’s surface and its support surface. Force measurement systems can be used in biomedical applications for gait analysis, mobility assessment, evaluation of sports performance, and ergonomics assessment. A force measurement system must include some form of force measurement device to quantify the forces and moments caused by the body placed thereon. The force measurement device can be any combination of a force plate, balance plate, force plate or jump plate depending on the application. Or it could be an instrumented treadmill that measures the forces and moments between the body’s support surface and the body.
A balance assessment of a human subject can be performed with a special type of force plate, also known as a balanceplate. The inputs of the vestibular, proprioceptive and visual systems help individuals to maintain their balance. The existence of conventional balance systems that can assess any one or more of these inputs is well-known. These conventional balance systems are often based on outdated technology, which can significantly reduce their accuracy in assessing a person’s weight and/or make them cumbersome and difficult for patients and operators (e.g. clinicians and other medical personnel). Some conventional balance systems use displaceable background enclosures that have fixed images on them. These are difficult to adapt to different testing methods.
“A force measurement system that uses virtual reality scenarios or simulated environments to accurately assess the balance characteristics of a subject is required. This will allow for greater flexibility in balance assessment testing. A method for testing subjects that uses a force measurement system with flexible, interactive virtual reality scenarios or simulated environments is also needed. A force and motion measurement system that uses an immersive visual display device to allow subjects to be immersed in virtual reality scenarios or interactive games is also required.
“Accordingly, this invention is directed at a force measurement device that substantially eliminates one or more problems caused by the limitations and inconsistencies of the related art.”
“In accordance to one or several embodiments of this invention, there is a force measuring system that can be used to measure force. The force measurement apparatus has a surface that can receive at least one part of the subject’s body. It also includes at least one force sensor, which is configured to sense one or two measured quantities and output one, or more, signals that represent forces or moments that the subject applies to the surface. A force measurement system also includes a head mounted visual display device with an output screen. The head-mounted display device is configured to display one to three scenes so that the subject can view them.
“In another embodiment of the invention, the force measurement assembly takes the form of a static forceplate that stays stationary while the subject is placed thereon.”
“In yet another embodiment, the data processor device can manipulate one or more scenes on a head-mounted visual screen device in order to disturb a subject’s visual input during a balance test.
“In yet another embodiment, the data processor device is further configured so that the output forces or moments can be utilized to assess the subject’s response to one or more scenes on the output screen.
“According to one or more embodiments of this invention, a force measuring system is provided that includes a force assembly for receiving a subject. The force measurement apparatus has a top surface to receive at least one part of the subject’s body. It also contains at least one force sensor, which can sense one or several measured quantities and output one, or more, measurement signals that represent forces and/or moment being applied to top of force measurement assemblies by the subject. The force measurement system also includes at minimum one actuator that is operatively coupled with the force measuring assembly. The at least 1 actuator is configured to move the force measuring assembly. At least one visual screen device has an output screen. The at least 1 visual display device can display one or several scenes to allow the subject to view them. One or more data processors are operatively coupled the force measurements assembly, the least one actuator and the at most one visual display devices. These data processing devices are designed to receive one or two measurement signals from the subject and convert them into output forces or moments.
“A further embodiment of this invention includes a base assembly with a stationary section and a displaceable section, the force measuring system also comprises at least one actuator that rotates the force measurement apparatus relative to the stationary part of base assembly around a transverse rotational direction.”
“In yet another embodiment, at least one actuator includes a first actuator that rotates the force measurement apparatus about the transverse rotational direction and a second actuator that translate the displacement portion of the base assembly which contains the force measurement assemblies.”
“A further embodiment of the visual display devices is a head-mounted device with an output screen. The output screen of the head mounted visual display device is configured to partially circumscribe a subject’s head so that the subject is immersed in the environment.
“In yet another embodiment, at least one visual device is in the shape of a head mounted visual display device. The head-mounted display device comprises one of a virtual or augmented reality headset.
“In yet another embodiment, one or more data processing device are further configured so that the force measurement assembly is displaced in order to perturb a subject’s proprioceptive input during a balance test.
“In yet another embodiment, one or more data processing device are further configured for the output forces and/or moment to assess the subject’s response to the displacement of force measurement assembly.”
“A further embodiment of the visual display device includes a flat or curved display screen.”
“Another embodiment of the visual display device includes a curved screen or multiple flat display screens that are arranged in concave arrangements so as to at minimum partially circumscribe the three sides and torsos of the subject.”
“Another embodiment allows the data processing devices to further manipulate one or more scenes on a visual display device’s output screen in order to disturb a subject’s visual input during a balance test, or other training routines where one or several sensory inputs are altered.”
“Another embodiment of the force measurement system includes an eye movement tracker that tracks the eye position and eye movement of the subject during the balance test or training program. The eye movement tracker is configured to output one to several eye tracking signals to one or multiple data processing devices. Further, the data processing devices can also use the eye tracking signals to evaluate the subject’s response to the perturbed vision input.
“According to one or more embodiments of this invention, there is a force measuring system that can be used to measure force. The force measurement apparatus has a surface that can receive at least one part of the subject’s body. It also includes at least one force sensor, which can sense one or several measured quantities and output one of the signals that represent the forces or moments that the subject applies to the force measurement assemblies. The force measurement system also includes a head mounted visual display device with an output screen. The output screen is configured to show one or several scenes to the subject. The one or two scenes are designed to create a simulated or augmented environment for them. A data processing device that is operatively coupled to both the force measurement apparatus and the head mount visual display device, which is configured to receive one or multiple signals that represent the forces or moments that the subject applies to the force measuring assembly’s surface. It can then convert those signals into output forces
“In another embodiment of the invention, the force measurement assembly takes the form of a static forceplate that stays stationary while the subject is placed thereon.”
“In yet another embodiment, the head mounted visual display device has at least 50 degree horizontal and 50 degree vertical fields of view.”
“In yet another embodiment, the force measurement device further includes an additional visual device operatively coupled with the data processor device. The data processing devices is configured to generate one to three scenes of the simulated or augmented environment which are displayed on a head-mounted visual device. Additionally, the data processing devices is further configured for one or more clinician screens, which are displayed on a second visual display visible to a clinician.
“Another embodiment includes at least one target, marker, and displaceable indicator that are displayed on the head mounted visual display device. The data processing device is set up to control movement of the at minimum one displaceable indicator towards the target or marker using one or more computed numerical value determined by the output forces or moments.
“It should be understood that both the above general description and the detailed description of this invention are only exemplary and informative in nature. The appended claims are not to be limited by the general description or the detailed description that follows.
“BRIEF DESCRIPTION ABOUT THE VIEWS FROM THE DRAWINGS”
“The invention will be described now, using an example and referring to the accompanying illustrations, which include:
“FIG. “FIG.
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“FIG. “FIG.7 is a top view of another force measurement unit used in the force measuring system, with exemplary coordinates axes superimposed thereon. According to an embodiment, the invention, the force measurement apparatus is in the form a single force plate.
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“FIG. “FIG. 11. is a block diagram of components of the force measuring system with a displaceable force assembly, according an embodiment of the invention.
“FIG. “FIG. 12 is a block illustration of data manipulation operations and motion controls carried out by force measurement systems, according to an embodiment.
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“FIG. “FIG. 20 is an interactive game in a second version that is displayed on the subject visual device of the force measuring system. According to an embodiment, the game element is at a fourth position.
“FIG. “FIG.
“FIG. “FIG. 22 is a first version of a training screen image that is displayed on the subject visual device of the force measuring system according to an embodiment;
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG. 25 is a third version of an interactive gaming displayed on the subject visual device of force measurement system. According to an embodiment, the interactive game has one or more targets, and a game element in a first place;
“FIG. “FIG. 26 is a third version of an interactive gaming displayed on the subject visual device of force measurement system. According to an embodiment, the interactive game has one or more targets, and the game element is placed in a second place;
“FIG. “FIG.27 is another example of interactive gaming displayed on the subject visually display device of force measurement system according to an embodiment. The interactive game is an interactive skiing game.
“FIG. “FIG. 28 is a top view diagrammatic of the base assembly, and the immersive subject vision display device of force measurement system according an alternate embodiment of the invention. In this alternative embodiment, a projector with fisheye lenses is placed in front of the visual device and behind the subject.
“FIG. 29 is a side view diagram of the base assembly, and the immersive subject video display device of force measurement system according an alternative embodiment. The projector with fisheye lens is located in front of the visual device and behind the subject.
“FIG. 30 is a top view of the base assembly, and the immersive subject visual-display device of force measurement system. According to an alternative embodiment of the invention, two projectors with fisheye lenses are placed in front and behind the subject.
“FIG. 31 is a side view showing the base assembly and the immersive subject video display device of force measurement system according yet another embodiment of the invention. The two projectors with their respective fisheye lenses are located in front and behind the subject.
“FIG. 32 is a top view diagrammatic of a force-motion measurement system with a motion acquisition/capture device, according to an embodiment. The motion acquisition/capture is illustrated with the base assembly and the immersive subject visual demonstration device and a subject having multiple markers;
“FIG. “FIG. 33 is a perspective of a force-motion measurement system with a motion acquisition/capture device, according to an embodiment. The motion acquisition/capture device is illustrated with the base assembly and the immersive subject visual demonstration device. A subject has a plurality markers disposed thereon.
“FIG. “FIG. 34 is a block diagram showing a calculation procedure to calculate joint angles, velocities and accelerations and a calculation procedure to calculate joint forces and moments. Both are performed by the force-motion measurement system according an embodiment of the invention.
“FIG. 35 is a diagrammatic view showing a human foot with its typical bone structure and certain elements of the FIG. 36 are superimposed thereon according to an exemplary embodiment.
“FIG. 36 is a free-body diagram that diagrammatically depicts the forces and moments at the ankle joint, according to an exemplary embodiment.
“FIG. “FIG. 37 is a third example showing a virtual reality scene on the subject visual screen device of the force measuring system, according an embodiment of the invention.
“FIG. 38 is a diagrammatic perspective of an alternative force measurement device consisting of an instrumented treadmill, and an enlarged hexagonal projection screen. This view is according to an embodiment the invention.
“FIG. 39A is a side view schematic of a motion base according an embodiment of the invention.
“FIG. 39B is a frontal schematic view of a motion platform according to an embodiment the invention;
“FIG. “FIG. 40 is a fourth example for a virtual reality scene that can be displayed on the subject-visual display device of force measurement system. The avatar in the virtual reality scene, according to an embodiment, is an avatar.
“FIG. 41 is the fifth example of a virtual world scene displayed on the subject visually display device of force measurement system. According to an embodiment, the virtual reality scene includes another avatar.
“FIG. 42 is a top-view of the base assembly illustrated at FIGS. 2, and 3 according to an embodiment the invention;
“FIG. FIG. 43 shows a section that is cut along the base assembly. 42. The section is cut along FIG. 42 according to one embodiment of the invention
“FIG. 44 is a perspective of the base assembly, the immersive subject visual device of force measurement system according another embodiment of the invention. A projector with an angle fisheye lens is mounted on top of this visual display device.
“FIG. “FIG.
“FIG. “FIG. 46 is a perspective of another alternative force measurement system, comprising a displacement visual surround device, base assembly and displaceable force measuring assembly, according an embodiment of the invention.
“FIG. “FIG.
“FIG. “FIG.48 is a second version of a screen picture consisting of a plurality generally concentric bars displayed on the subject-visual display device of force measurement system. According to an embodiment, the plurality concentric bands are generally oval or elliptical in shape.
“FIG. 49 shows a perspective view showing a force-motion measurement system with a motion detection method, according to an embodiment. The motion detection system includes a plurality IMUs (inertial measurement units) that detect the subject’s motion.
“FIG. “FIG.
“FIG. 51A is a diagrammatic view showing a subject wearing augmented realities glasses, positioned on a force measurement apparatus. The subject is in an upright position and the image of scenery seen by him through the augmented glasses is generally the same as the view captured by the camera(s).
“FIG. “FIG.
“FIG. 51C is a third diagrammatic image of a subject wearing an augmented reality glass and positioned on a force measurement apparatus. The subject is in a forwardly disposed position on the force measurement apparatus, and the image of scenery seen by the subject through the glasses has been altered so that it doesn’t match the actual view captured by the camera(s).
“FIG. 52 shows a perspective view showing a subject placed on a static force measurement apparatus and positioned within an immersive subject vision display device according to another embodiment of the invention.
“FIG. 53 shows a perspective view showing a subject wearing an eye-mounted visual display device that is mounted on a displaceable force measuring assembly. This is another embodiment of the invention.
“The same parts in the figures are always denoted using the exact same reference characters. This means that they will be described only once.
“An exemplary embodiment is shown at 100 in FIG. 1. The illustrative embodiment of the force measurement system 100 includes a force measurement apparatus 102 that is operatively connected to a dataacquisition/data processing device (i.e., any device capable of collecting, processing, and storing data) which is in turn operatively coupled with a subject visual display display device 107 or an operator visual display unit 130. FIG. FIG. 1 shows how the force measurement assembly (102) can receive a subject. It is capable of measuring forces and/or moments on its substantially plane measurement surfaces 114 and 116 by the subject.
“As shown at FIG. “As shown in FIG. 1, the data acquisition/data processor device 104 includes a plurality user input devices 132 and 134 connected thereto. The preferred user input devices 132,134 include a keyboard 132 and mouse 134. If it has touch screen capabilities, the operator visual display devices 130 can also be used as user input devices. FIG. 1 shows a desktop-type computing device. FIG. 1 shows a desktop-type computing system. However, one of ordinary skill in the arts will recognize that a different type of data acquisition/data processor device 104 could be used to replace the desktop computing system. This includes, but is not limited, to a laptop or a handheld computing device (i.e. a PDA). It is also possible to provide a data processing device/data acquisition device 104 without departing from its spirit and scope.
Referring to FIG. “Referring again to FIG. 1, it is clear that the force measurement apparatus 102 in the illustrated embodiment takes the form of a dual-force plate assembly. Displaceable, dual force plates include a first component 110 and a second component 112. At least one force measurement instrument (e.g. a force transmitter) is associated with the first component 110. The second component 112. The illustrated embodiment shows a subject 108 standing upright on the force measurement apparatus 102. Each foot of the subject is placed on top surfaces 110, 116 of respective plate components 110, 112, (i.e. one foot on top of first plate component 110 and another foot on top of second plate component 112). The first plate component 110 has at least one of its force transducers. This allows it to sense one or several measured quantities, and output one/more first signals. Each foot of the subject 108 is placed on the top surfaces 114, 116 of a respective plate component 110. The second plate component 112 has at least one force transmitter. It is designed to sense one/more measured quantities and output one/more second signals. These signals are representative forces and/or moment being applied to the measurement surface 116 by subject 108 One or more embodiments of the force measurement system 102 ensure that the subject 108 does not move relative the displaceable force measurement apparatus 102. In other words, the subject moves in sync with the force measurement apparatus 102 when it is moved on the plate component 110. In one or more embodiments, top surfaces 110, 116 of respective plate components 110, 112 do not rotate under the feet 108 of the subject, but instead remain stationary relative to the feet 108 (i.e. the top surfaces of 114 and 116 are generally displaced in the same way as the feet).
“In one non-limiting, illustrated embodiment, the forceplate assembly 102 has a maximum load capacity of approximately 500 lbs. (up to approximately 2224 N or 500 lbs. (up to 2,224 n). This high load capacity allows the force plate 102 to be used on almost any subject that requires testing on force plate 102. The force plate assembly 102 is non-limiting in that it measures approximately 18 inches by 20 inches (20 inches). But, an ordinary person skilled in the art will recognize that force plate assembly 102 can be made with other dimensions.
“Now, refer to FIG. 2 shows that the displaceable force measurement apparatus 102 is movably connected to a base assembly (106). The base assembly 106 typically consists of a central portion 106b that is substantially rectangular and two side enclosures 106a,106c that are spaced apart and are located on opposite sides of the center portion. FIG. FIG. 2 shows the displaceable force measurement apparatus 102 recessed-mounted into 106b of base assembly 106 (i.e. it is recess mounted into the top of the translatablesled assembly 156) so its upper surface is substantially flush with the stationary top surfaces 122a, 122b of center portion106b of base assembly106. The top surface of displaceable force measurement apparatus 102 is also substantially flush with that of translatable sled 156. In the illustrated embodiment, you can see that the base assembly (106) also includes two mounting brackets 124, which are positioned on the side enclosures 106a,106c. Each bracket 124 holds a support rail 128. You can use the support rails 128 for many purposes. The support rails 128 could be used to support a safety harness system that is worn by the subject during testing to prevent injury.
Referring to FIG. “Referring again to FIG. The bottom of each side enclosure (106 a,106 c) is open so that the waste heat can be vented. FIG. FIG. 2 shows that the side enclosure (106a) contains an emergency stop switch (138 or E-stop) located in the rear, diagonal panel. In one embodiment, the emergency stop switch 138 is in the form of a red pushbutton that can be easily pressed by a user of the force measurement system 100 in order to quasi-instantaneously stop the displacement of the force measurement assembly 102. The emergency stop switch 138 protects the subject who is placed on the displaceable force measuring assembly 102 against injury.
“Next, turn to FIG. “Next, turning to FIG. 3 will be described in detail the drive components for the base assembly. In this section, we will first explain the actuator system that produces the translation of force measurement assembly (102). FIG. FIG. 3 shows the front cover of the central portion 106b of the base assembly106 that has been removed to expose the translation drive components. The force measurement assembly (102) is shown in the figure. It is mounted to a translatable shaft assembly 156. The translatable assembly 156 can be moved forward and backward, i.e. in directions that are generally parallel to the sagittal plan SP of the subject (see FIG. 1) is mounted on the force measurement apparatus 102, by means of a first actuator 158. The first actuator assembly (158) moves the translatable assembly 156 forwards and backwards without any rotation or angular displacement. The illustrated embodiment of the first actuator assembly (158) is a ball screw actuator and includes an electrical motor that drives a rotating screw shaft, which in turn is threadingly coupled with a nut attached to the translatable assembly 156. The translatable sled is moved along a linear path when the screw shaft of first actuator assembly 158 rotates by the electric motor. The first actuator assembly 158’s electric motor is operatively coupled with a gearbox (e.g., a 4:3 gear box), which in turn drives the rotatable shaft. The actuator assembly 158 is extremely efficient because the ball screw actuator’s nut runs on ball bearings. The back-driveability of the ball screw actuator design is a negative consequence. This could pose a safety risk to subjects positioned on the displaceable force measuring assembly 102. The force plate could inadvertently shift when the subject’s weight is applied to it. The first actuator assembly (158) is also equipped with a brake assembly that is located adjacent to the electric motor to prevent the force measurement apparatus 102 from being accidentally translated. The brake assembly of first actuator assembly (158) prevents accidental translation of force measurement assembly (102).
“In FIG. “In FIG.4.22, a top view is shown of the base assembly 106. In FIG.4.33, a longitudinal cross-sectional view of the base assembly106 is shown. 43 illustrates a longitudinal cross-sectional view showing the base assembly 106. FIGS. FIGS. 42 and 43 show that the force measurement assembly (102) is mounted on a rotating carriage assembly 157 (i.e. a swivelframe 157). Rotatable carriage assembly (157) is attached to and rotates relative the translatable skid assembly 156 (i.e. the translatable frame 56). A second actuator assembly 160 rotates the rotatable carriage assembly. (see FIG. 3) around a rotational shaft 163 43?the rotatable carriage assembly (157) is equipped with diagonal hatching. FIG. 43 shows that the rotatable carriage assembly (157) can be rotated clockwise or counterclockwise around the transverse rotational direction TA in FIG. 3. (i.e. generally a single degree of freedom rotation around the transverse axis, TA). Contrary to this, the FIGS. 161 straight arrows 161 indicate that. 42 and 43 show that the translatable assembly 156 can perform forward and backward translational movements by virtue of being linearly displace by the first actuator assembly 158. FIGS. FIGS. 42 and 43 show a rearwardly displaced location 156a of the translatable skid assembly 156. A forwardly displaced place 156b of the translatable skid assembly 156 can be indicated with dashed lines with small dots.
Referring to FIG. 3. The actuator system that produces the rotation of force measurement assembly102 will be described. FIG. FIG. 3 shows the removal of the top cover of the side assembly 106 c to expose the rotational drive components. The second actuator assembly 160 rotates the force measurement assembly (102) within the translatable shaft assembly 156. The second actuator assembly 160, which is similar to the first actuator assembly, 158, also includes an electric motor with gear box (e.g. a 4:1 gearbox) that drives a rotating screw shaft. This is then threadingly coupled with a nut that is driven by ball bearings. The second actuator assembly 160 includes a swing arm that is operatively coupled with the nut of a ball screw actuator, but it differs from the first actuator assembly. The swing arm is attached to the rotatable carrier assembly 157 with force measurement assembly 102, and rotates when the nut is moved along the screw shaft. The swing arm rotates around a transverse rotational angle TA when it is attached to the force measurement assembly. (see FIG. 3). The force measurement assembly 102 is subject to a generally one degree of freedom rotation around the transverse rotational direction TA. One embodiment of the force measurement apparatus 102 shows the imaginary transverse axis (TA) passing through the middle of the subject’s ankle joints 108. The second actuator assembly 160, which is also a highly efficient ball-screw actuator, includes a brake assembly adjacent to the electric engine to prevent it being back-driven. It is similar to the first actuator assembly (158). The brake assembly of second actuator assembly 160 stops the force measurement apparatus 102 from being accidentally rotated to protect the subject. The first actuator assembly 158 translates the translatable assembly 156. The second actuator assembly 160 then translates the sled assembly156 and force plate. The translatable sled 156 is translated by the first actuator assembly (158) backwards or forwards. The second actuator assembly 160 is then displaced along the rail or rod of base assembly 106.
“In the preferred embodiment of this invention, the first actuator assembly (158) and second actuator assembly 160 have two (2) electrical cables that are operatively connected thereto. The first cable connecting to each actuator assembly 160, 158 is a power cable that powers the electric motor and brakes of each actuator. The second cable transmits position information from each actuator encoder, which is used in feedback control of each actuator assembly 160, 158.
“Referring to FIG. “Referring to FIG. 1, you can see that the base assembly (106) is operatively connected to the data acquisition/data processor device 104 via an electrical cable 118. The electrical cable number 118 is used to transmit data between the programmable controller (PLC), of the base assembly (106), and the data acquisition/data processor device (104, i.e. the operator computing device (104). Cable 118 can be used with a variety of data transmission cables. Cable 118 could be either an Ethernet or Universal Serial Bus (USB), for example. The preferred electrical cable 118 has a number of wires that are bundled together and used for data transmission. It is possible to operatively connect the base assembly (106) to the data acquisition/data processor device 104 by using another signal transmission method, such as a wireless transmission system.
“In the illustrated embodiment, at least one force transmitter associated with the first or second plate components 110, 112 comprises four (four) pylon type force transducers (or pylon style load cells), that are located underneath and near each of four corners (4) (see FIG. 4). Each of the eight (8) illustrated pylon type force transducers has a plurality strain gages attached to the outer perimeter of a cylindrically-shaped force sensor element for detecting mechanical strain imparted thereon from the force(s). FIG. FIG. 4 shows that each plate component 110, 112 has a base plate 162 underneath it. This allows for the mounting of the forceplate assembly to the rotatable carriage 157 of translatable sled 156 of base assembly 106. A plurality of structural frames members, such as steel, could be used instead of the base plates 162 to attach the dual force plate assembly the the rotatable carriage 157 of translatable sled 156 of base assembly 106.
“In an alternative embodiment, instead of using four (4) pylon type force transducers (154) on each plate components 110, 112, force transmitters in the form transducer beams could also be placed under each plate component 110 and 112. This alternative embodiment could include two transducer beams underneath the first plate 110, which would be on opposite sides of the first 110 plate. In this same embodiment, the second component 112 could also contain two transducer beams. They would be located underneath and on opposite sides of second component 112. The force transducer beams may have multiple strain gages attached on one or more of their surfaces, similar to the pylon-type force transmitters 154. This allows for the measurement of mechanical strain caused by force applied to the surface of the force measurement apparatus 102.
Summary for “Force measurement system”
“1. “1.
“The invention generally refers to a force measurement device. The invention is more specifically related to a force measurement system and a method of testing subjects using that system.
“2. Background”
“Force measurement systems can be used in many fields to measure the reaction forces and moments between a body’s surface and its support surface. Force measurement systems can be used in biomedical applications for gait analysis, mobility assessment, evaluation of sports performance, and ergonomics assessment. A force measurement system must include some form of force measurement device to quantify the forces and moments caused by the body placed thereon. The force measurement device can be any combination of a force plate, balance plate, force plate or jump plate depending on the application. Or it could be an instrumented treadmill that measures the forces and moments between the body’s support surface and the body.
A balance assessment of a human subject can be performed with a special type of force plate, also known as a balanceplate. The inputs of the vestibular, proprioceptive and visual systems help individuals to maintain their balance. The existence of conventional balance systems that can assess any one or more of these inputs is well-known. These conventional balance systems are often based on outdated technology, which can significantly reduce their accuracy in assessing a person’s weight and/or make them cumbersome and difficult for patients and operators (e.g. clinicians and other medical personnel). Some conventional balance systems use displaceable background enclosures that have fixed images on them. These are difficult to adapt to different testing methods.
“A force measurement system that uses virtual reality scenarios or simulated environments to accurately assess the balance characteristics of a subject is required. This will allow for greater flexibility in balance assessment testing. A method for testing subjects that uses a force measurement system with flexible, interactive virtual reality scenarios or simulated environments is also needed. A force and motion measurement system that uses an immersive visual display device to allow subjects to be immersed in virtual reality scenarios or interactive games is also required.
“Accordingly, this invention is directed at a force measurement device that substantially eliminates one or more problems caused by the limitations and inconsistencies of the related art.”
“In accordance to one or several embodiments of this invention, there is a force measuring system that can be used to measure force. The force measurement apparatus has a surface that can receive at least one part of the subject’s body. It also includes at least one force sensor, which is configured to sense one or two measured quantities and output one, or more, signals that represent forces or moments that the subject applies to the surface. A force measurement system also includes a head mounted visual display device with an output screen. The head-mounted display device is configured to display one to three scenes so that the subject can view them.
“In another embodiment of the invention, the force measurement assembly takes the form of a static forceplate that stays stationary while the subject is placed thereon.”
“In yet another embodiment, the data processor device can manipulate one or more scenes on a head-mounted visual screen device in order to disturb a subject’s visual input during a balance test.
“In yet another embodiment, the data processor device is further configured so that the output forces or moments can be utilized to assess the subject’s response to one or more scenes on the output screen.
“According to one or more embodiments of this invention, a force measuring system is provided that includes a force assembly for receiving a subject. The force measurement apparatus has a top surface to receive at least one part of the subject’s body. It also contains at least one force sensor, which can sense one or several measured quantities and output one, or more, measurement signals that represent forces and/or moment being applied to top of force measurement assemblies by the subject. The force measurement system also includes at minimum one actuator that is operatively coupled with the force measuring assembly. The at least 1 actuator is configured to move the force measuring assembly. At least one visual screen device has an output screen. The at least 1 visual display device can display one or several scenes to allow the subject to view them. One or more data processors are operatively coupled the force measurements assembly, the least one actuator and the at most one visual display devices. These data processing devices are designed to receive one or two measurement signals from the subject and convert them into output forces or moments.
“A further embodiment of this invention includes a base assembly with a stationary section and a displaceable section, the force measuring system also comprises at least one actuator that rotates the force measurement apparatus relative to the stationary part of base assembly around a transverse rotational direction.”
“In yet another embodiment, at least one actuator includes a first actuator that rotates the force measurement apparatus about the transverse rotational direction and a second actuator that translate the displacement portion of the base assembly which contains the force measurement assemblies.”
“A further embodiment of the visual display devices is a head-mounted device with an output screen. The output screen of the head mounted visual display device is configured to partially circumscribe a subject’s head so that the subject is immersed in the environment.
“In yet another embodiment, at least one visual device is in the shape of a head mounted visual display device. The head-mounted display device comprises one of a virtual or augmented reality headset.
“In yet another embodiment, one or more data processing device are further configured so that the force measurement assembly is displaced in order to perturb a subject’s proprioceptive input during a balance test.
“In yet another embodiment, one or more data processing device are further configured for the output forces and/or moment to assess the subject’s response to the displacement of force measurement assembly.”
“A further embodiment of the visual display device includes a flat or curved display screen.”
“Another embodiment of the visual display device includes a curved screen or multiple flat display screens that are arranged in concave arrangements so as to at minimum partially circumscribe the three sides and torsos of the subject.”
“Another embodiment allows the data processing devices to further manipulate one or more scenes on a visual display device’s output screen in order to disturb a subject’s visual input during a balance test, or other training routines where one or several sensory inputs are altered.”
“Another embodiment of the force measurement system includes an eye movement tracker that tracks the eye position and eye movement of the subject during the balance test or training program. The eye movement tracker is configured to output one to several eye tracking signals to one or multiple data processing devices. Further, the data processing devices can also use the eye tracking signals to evaluate the subject’s response to the perturbed vision input.
“According to one or more embodiments of this invention, there is a force measuring system that can be used to measure force. The force measurement apparatus has a surface that can receive at least one part of the subject’s body. It also includes at least one force sensor, which can sense one or several measured quantities and output one of the signals that represent the forces or moments that the subject applies to the force measurement assemblies. The force measurement system also includes a head mounted visual display device with an output screen. The output screen is configured to show one or several scenes to the subject. The one or two scenes are designed to create a simulated or augmented environment for them. A data processing device that is operatively coupled to both the force measurement apparatus and the head mount visual display device, which is configured to receive one or multiple signals that represent the forces or moments that the subject applies to the force measuring assembly’s surface. It can then convert those signals into output forces
“In another embodiment of the invention, the force measurement assembly takes the form of a static forceplate that stays stationary while the subject is placed thereon.”
“In yet another embodiment, the head mounted visual display device has at least 50 degree horizontal and 50 degree vertical fields of view.”
“In yet another embodiment, the force measurement device further includes an additional visual device operatively coupled with the data processor device. The data processing devices is configured to generate one to three scenes of the simulated or augmented environment which are displayed on a head-mounted visual device. Additionally, the data processing devices is further configured for one or more clinician screens, which are displayed on a second visual display visible to a clinician.
“Another embodiment includes at least one target, marker, and displaceable indicator that are displayed on the head mounted visual display device. The data processing device is set up to control movement of the at minimum one displaceable indicator towards the target or marker using one or more computed numerical value determined by the output forces or moments.
“It should be understood that both the above general description and the detailed description of this invention are only exemplary and informative in nature. The appended claims are not to be limited by the general description or the detailed description that follows.
“BRIEF DESCRIPTION ABOUT THE VIEWS FROM THE DRAWINGS”
“The invention will be described now, using an example and referring to the accompanying illustrations, which include:
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.7 is a top view of another force measurement unit used in the force measuring system, with exemplary coordinates axes superimposed thereon. According to an embodiment, the invention, the force measurement apparatus is in the form a single force plate.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG. 11. is a block diagram of components of the force measuring system with a displaceable force assembly, according an embodiment of the invention.
“FIG. “FIG. 12 is a block illustration of data manipulation operations and motion controls carried out by force measurement systems, according to an embodiment.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG. 20 is an interactive game in a second version that is displayed on the subject visual device of the force measuring system. According to an embodiment, the game element is at a fourth position.
“FIG. “FIG.
“FIG. “FIG. 22 is a first version of a training screen image that is displayed on the subject visual device of the force measuring system according to an embodiment;
“FIG. “FIG.
“FIG. “FIG.
“FIG. “FIG. 25 is a third version of an interactive gaming displayed on the subject visual device of force measurement system. According to an embodiment, the interactive game has one or more targets, and a game element in a first place;
“FIG. “FIG. 26 is a third version of an interactive gaming displayed on the subject visual device of force measurement system. According to an embodiment, the interactive game has one or more targets, and the game element is placed in a second place;
“FIG. “FIG.27 is another example of interactive gaming displayed on the subject visually display device of force measurement system according to an embodiment. The interactive game is an interactive skiing game.
“FIG. “FIG. 28 is a top view diagrammatic of the base assembly, and the immersive subject vision display device of force measurement system according an alternate embodiment of the invention. In this alternative embodiment, a projector with fisheye lenses is placed in front of the visual device and behind the subject.
“FIG. 29 is a side view diagram of the base assembly, and the immersive subject video display device of force measurement system according an alternative embodiment. The projector with fisheye lens is located in front of the visual device and behind the subject.
“FIG. 30 is a top view of the base assembly, and the immersive subject visual-display device of force measurement system. According to an alternative embodiment of the invention, two projectors with fisheye lenses are placed in front and behind the subject.
“FIG. 31 is a side view showing the base assembly and the immersive subject video display device of force measurement system according yet another embodiment of the invention. The two projectors with their respective fisheye lenses are located in front and behind the subject.
“FIG. 32 is a top view diagrammatic of a force-motion measurement system with a motion acquisition/capture device, according to an embodiment. The motion acquisition/capture is illustrated with the base assembly and the immersive subject visual demonstration device and a subject having multiple markers;
“FIG. “FIG. 33 is a perspective of a force-motion measurement system with a motion acquisition/capture device, according to an embodiment. The motion acquisition/capture device is illustrated with the base assembly and the immersive subject visual demonstration device. A subject has a plurality markers disposed thereon.
“FIG. “FIG. 34 is a block diagram showing a calculation procedure to calculate joint angles, velocities and accelerations and a calculation procedure to calculate joint forces and moments. Both are performed by the force-motion measurement system according an embodiment of the invention.
“FIG. 35 is a diagrammatic view showing a human foot with its typical bone structure and certain elements of the FIG. 36 are superimposed thereon according to an exemplary embodiment.
“FIG. 36 is a free-body diagram that diagrammatically depicts the forces and moments at the ankle joint, according to an exemplary embodiment.
“FIG. “FIG. 37 is a third example showing a virtual reality scene on the subject visual screen device of the force measuring system, according an embodiment of the invention.
“FIG. 38 is a diagrammatic perspective of an alternative force measurement device consisting of an instrumented treadmill, and an enlarged hexagonal projection screen. This view is according to an embodiment the invention.
“FIG. 39A is a side view schematic of a motion base according an embodiment of the invention.
“FIG. 39B is a frontal schematic view of a motion platform according to an embodiment the invention;
“FIG. “FIG. 40 is a fourth example for a virtual reality scene that can be displayed on the subject-visual display device of force measurement system. The avatar in the virtual reality scene, according to an embodiment, is an avatar.
“FIG. 41 is the fifth example of a virtual world scene displayed on the subject visually display device of force measurement system. According to an embodiment, the virtual reality scene includes another avatar.
“FIG. 42 is a top-view of the base assembly illustrated at FIGS. 2, and 3 according to an embodiment the invention;
“FIG. FIG. 43 shows a section that is cut along the base assembly. 42. The section is cut along FIG. 42 according to one embodiment of the invention
“FIG. 44 is a perspective of the base assembly, the immersive subject visual device of force measurement system according another embodiment of the invention. A projector with an angle fisheye lens is mounted on top of this visual display device.
“FIG. “FIG.
“FIG. “FIG. 46 is a perspective of another alternative force measurement system, comprising a displacement visual surround device, base assembly and displaceable force measuring assembly, according an embodiment of the invention.
“FIG. “FIG.
“FIG. “FIG.48 is a second version of a screen picture consisting of a plurality generally concentric bars displayed on the subject-visual display device of force measurement system. According to an embodiment, the plurality concentric bands are generally oval or elliptical in shape.
“FIG. 49 shows a perspective view showing a force-motion measurement system with a motion detection method, according to an embodiment. The motion detection system includes a plurality IMUs (inertial measurement units) that detect the subject’s motion.
“FIG. “FIG.
“FIG. 51A is a diagrammatic view showing a subject wearing augmented realities glasses, positioned on a force measurement apparatus. The subject is in an upright position and the image of scenery seen by him through the augmented glasses is generally the same as the view captured by the camera(s).
“FIG. “FIG.
“FIG. 51C is a third diagrammatic image of a subject wearing an augmented reality glass and positioned on a force measurement apparatus. The subject is in a forwardly disposed position on the force measurement apparatus, and the image of scenery seen by the subject through the glasses has been altered so that it doesn’t match the actual view captured by the camera(s).
“FIG. 52 shows a perspective view showing a subject placed on a static force measurement apparatus and positioned within an immersive subject vision display device according to another embodiment of the invention.
“FIG. 53 shows a perspective view showing a subject wearing an eye-mounted visual display device that is mounted on a displaceable force measuring assembly. This is another embodiment of the invention.
“The same parts in the figures are always denoted using the exact same reference characters. This means that they will be described only once.
“An exemplary embodiment is shown at 100 in FIG. 1. The illustrative embodiment of the force measurement system 100 includes a force measurement apparatus 102 that is operatively connected to a dataacquisition/data processing device (i.e., any device capable of collecting, processing, and storing data) which is in turn operatively coupled with a subject visual display display device 107 or an operator visual display unit 130. FIG. FIG. 1 shows how the force measurement assembly (102) can receive a subject. It is capable of measuring forces and/or moments on its substantially plane measurement surfaces 114 and 116 by the subject.
“As shown at FIG. “As shown in FIG. 1, the data acquisition/data processor device 104 includes a plurality user input devices 132 and 134 connected thereto. The preferred user input devices 132,134 include a keyboard 132 and mouse 134. If it has touch screen capabilities, the operator visual display devices 130 can also be used as user input devices. FIG. 1 shows a desktop-type computing device. FIG. 1 shows a desktop-type computing system. However, one of ordinary skill in the arts will recognize that a different type of data acquisition/data processor device 104 could be used to replace the desktop computing system. This includes, but is not limited, to a laptop or a handheld computing device (i.e. a PDA). It is also possible to provide a data processing device/data acquisition device 104 without departing from its spirit and scope.
Referring to FIG. “Referring again to FIG. 1, it is clear that the force measurement apparatus 102 in the illustrated embodiment takes the form of a dual-force plate assembly. Displaceable, dual force plates include a first component 110 and a second component 112. At least one force measurement instrument (e.g. a force transmitter) is associated with the first component 110. The second component 112. The illustrated embodiment shows a subject 108 standing upright on the force measurement apparatus 102. Each foot of the subject is placed on top surfaces 110, 116 of respective plate components 110, 112, (i.e. one foot on top of first plate component 110 and another foot on top of second plate component 112). The first plate component 110 has at least one of its force transducers. This allows it to sense one or several measured quantities, and output one/more first signals. Each foot of the subject 108 is placed on the top surfaces 114, 116 of a respective plate component 110. The second plate component 112 has at least one force transmitter. It is designed to sense one/more measured quantities and output one/more second signals. These signals are representative forces and/or moment being applied to the measurement surface 116 by subject 108 One or more embodiments of the force measurement system 102 ensure that the subject 108 does not move relative the displaceable force measurement apparatus 102. In other words, the subject moves in sync with the force measurement apparatus 102 when it is moved on the plate component 110. In one or more embodiments, top surfaces 110, 116 of respective plate components 110, 112 do not rotate under the feet 108 of the subject, but instead remain stationary relative to the feet 108 (i.e. the top surfaces of 114 and 116 are generally displaced in the same way as the feet).
“In one non-limiting, illustrated embodiment, the forceplate assembly 102 has a maximum load capacity of approximately 500 lbs. (up to approximately 2224 N or 500 lbs. (up to 2,224 n). This high load capacity allows the force plate 102 to be used on almost any subject that requires testing on force plate 102. The force plate assembly 102 is non-limiting in that it measures approximately 18 inches by 20 inches (20 inches). But, an ordinary person skilled in the art will recognize that force plate assembly 102 can be made with other dimensions.
“Now, refer to FIG. 2 shows that the displaceable force measurement apparatus 102 is movably connected to a base assembly (106). The base assembly 106 typically consists of a central portion 106b that is substantially rectangular and two side enclosures 106a,106c that are spaced apart and are located on opposite sides of the center portion. FIG. FIG. 2 shows the displaceable force measurement apparatus 102 recessed-mounted into 106b of base assembly 106 (i.e. it is recess mounted into the top of the translatablesled assembly 156) so its upper surface is substantially flush with the stationary top surfaces 122a, 122b of center portion106b of base assembly106. The top surface of displaceable force measurement apparatus 102 is also substantially flush with that of translatable sled 156. In the illustrated embodiment, you can see that the base assembly (106) also includes two mounting brackets 124, which are positioned on the side enclosures 106a,106c. Each bracket 124 holds a support rail 128. You can use the support rails 128 for many purposes. The support rails 128 could be used to support a safety harness system that is worn by the subject during testing to prevent injury.
Referring to FIG. “Referring again to FIG. The bottom of each side enclosure (106 a,106 c) is open so that the waste heat can be vented. FIG. FIG. 2 shows that the side enclosure (106a) contains an emergency stop switch (138 or E-stop) located in the rear, diagonal panel. In one embodiment, the emergency stop switch 138 is in the form of a red pushbutton that can be easily pressed by a user of the force measurement system 100 in order to quasi-instantaneously stop the displacement of the force measurement assembly 102. The emergency stop switch 138 protects the subject who is placed on the displaceable force measuring assembly 102 against injury.
“Next, turn to FIG. “Next, turning to FIG. 3 will be described in detail the drive components for the base assembly. In this section, we will first explain the actuator system that produces the translation of force measurement assembly (102). FIG. FIG. 3 shows the front cover of the central portion 106b of the base assembly106 that has been removed to expose the translation drive components. The force measurement assembly (102) is shown in the figure. It is mounted to a translatable shaft assembly 156. The translatable assembly 156 can be moved forward and backward, i.e. in directions that are generally parallel to the sagittal plan SP of the subject (see FIG. 1) is mounted on the force measurement apparatus 102, by means of a first actuator 158. The first actuator assembly (158) moves the translatable assembly 156 forwards and backwards without any rotation or angular displacement. The illustrated embodiment of the first actuator assembly (158) is a ball screw actuator and includes an electrical motor that drives a rotating screw shaft, which in turn is threadingly coupled with a nut attached to the translatable assembly 156. The translatable sled is moved along a linear path when the screw shaft of first actuator assembly 158 rotates by the electric motor. The first actuator assembly 158’s electric motor is operatively coupled with a gearbox (e.g., a 4:3 gear box), which in turn drives the rotatable shaft. The actuator assembly 158 is extremely efficient because the ball screw actuator’s nut runs on ball bearings. The back-driveability of the ball screw actuator design is a negative consequence. This could pose a safety risk to subjects positioned on the displaceable force measuring assembly 102. The force plate could inadvertently shift when the subject’s weight is applied to it. The first actuator assembly (158) is also equipped with a brake assembly that is located adjacent to the electric motor to prevent the force measurement apparatus 102 from being accidentally translated. The brake assembly of first actuator assembly (158) prevents accidental translation of force measurement assembly (102).
“In FIG. “In FIG.4.22, a top view is shown of the base assembly 106. In FIG.4.33, a longitudinal cross-sectional view of the base assembly106 is shown. 43 illustrates a longitudinal cross-sectional view showing the base assembly 106. FIGS. FIGS. 42 and 43 show that the force measurement assembly (102) is mounted on a rotating carriage assembly 157 (i.e. a swivelframe 157). Rotatable carriage assembly (157) is attached to and rotates relative the translatable skid assembly 156 (i.e. the translatable frame 56). A second actuator assembly 160 rotates the rotatable carriage assembly. (see FIG. 3) around a rotational shaft 163 43?the rotatable carriage assembly (157) is equipped with diagonal hatching. FIG. 43 shows that the rotatable carriage assembly (157) can be rotated clockwise or counterclockwise around the transverse rotational direction TA in FIG. 3. (i.e. generally a single degree of freedom rotation around the transverse axis, TA). Contrary to this, the FIGS. 161 straight arrows 161 indicate that. 42 and 43 show that the translatable assembly 156 can perform forward and backward translational movements by virtue of being linearly displace by the first actuator assembly 158. FIGS. FIGS. 42 and 43 show a rearwardly displaced location 156a of the translatable skid assembly 156. A forwardly displaced place 156b of the translatable skid assembly 156 can be indicated with dashed lines with small dots.
Referring to FIG. 3. The actuator system that produces the rotation of force measurement assembly102 will be described. FIG. FIG. 3 shows the removal of the top cover of the side assembly 106 c to expose the rotational drive components. The second actuator assembly 160 rotates the force measurement assembly (102) within the translatable shaft assembly 156. The second actuator assembly 160, which is similar to the first actuator assembly, 158, also includes an electric motor with gear box (e.g. a 4:1 gearbox) that drives a rotating screw shaft. This is then threadingly coupled with a nut that is driven by ball bearings. The second actuator assembly 160 includes a swing arm that is operatively coupled with the nut of a ball screw actuator, but it differs from the first actuator assembly. The swing arm is attached to the rotatable carrier assembly 157 with force measurement assembly 102, and rotates when the nut is moved along the screw shaft. The swing arm rotates around a transverse rotational angle TA when it is attached to the force measurement assembly. (see FIG. 3). The force measurement assembly 102 is subject to a generally one degree of freedom rotation around the transverse rotational direction TA. One embodiment of the force measurement apparatus 102 shows the imaginary transverse axis (TA) passing through the middle of the subject’s ankle joints 108. The second actuator assembly 160, which is also a highly efficient ball-screw actuator, includes a brake assembly adjacent to the electric engine to prevent it being back-driven. It is similar to the first actuator assembly (158). The brake assembly of second actuator assembly 160 stops the force measurement apparatus 102 from being accidentally rotated to protect the subject. The first actuator assembly 158 translates the translatable assembly 156. The second actuator assembly 160 then translates the sled assembly156 and force plate. The translatable sled 156 is translated by the first actuator assembly (158) backwards or forwards. The second actuator assembly 160 is then displaced along the rail or rod of base assembly 106.
“In the preferred embodiment of this invention, the first actuator assembly (158) and second actuator assembly 160 have two (2) electrical cables that are operatively connected thereto. The first cable connecting to each actuator assembly 160, 158 is a power cable that powers the electric motor and brakes of each actuator. The second cable transmits position information from each actuator encoder, which is used in feedback control of each actuator assembly 160, 158.
“Referring to FIG. “Referring to FIG. 1, you can see that the base assembly (106) is operatively connected to the data acquisition/data processor device 104 via an electrical cable 118. The electrical cable number 118 is used to transmit data between the programmable controller (PLC), of the base assembly (106), and the data acquisition/data processor device (104, i.e. the operator computing device (104). Cable 118 can be used with a variety of data transmission cables. Cable 118 could be either an Ethernet or Universal Serial Bus (USB), for example. The preferred electrical cable 118 has a number of wires that are bundled together and used for data transmission. It is possible to operatively connect the base assembly (106) to the data acquisition/data processor device 104 by using another signal transmission method, such as a wireless transmission system.
“In the illustrated embodiment, at least one force transmitter associated with the first or second plate components 110, 112 comprises four (four) pylon type force transducers (or pylon style load cells), that are located underneath and near each of four corners (4) (see FIG. 4). Each of the eight (8) illustrated pylon type force transducers has a plurality strain gages attached to the outer perimeter of a cylindrically-shaped force sensor element for detecting mechanical strain imparted thereon from the force(s). FIG. FIG. 4 shows that each plate component 110, 112 has a base plate 162 underneath it. This allows for the mounting of the forceplate assembly to the rotatable carriage 157 of translatable sled 156 of base assembly 106. A plurality of structural frames members, such as steel, could be used instead of the base plates 162 to attach the dual force plate assembly the the rotatable carriage 157 of translatable sled 156 of base assembly 106.
“In an alternative embodiment, instead of using four (4) pylon type force transducers (154) on each plate components 110, 112, force transmitters in the form transducer beams could also be placed under each plate component 110 and 112. This alternative embodiment could include two transducer beams underneath the first plate 110, which would be on opposite sides of the first 110 plate. In this same embodiment, the second component 112 could also contain two transducer beams. They would be located underneath and on opposite sides of second component 112. The force transducer beams may have multiple strain gages attached on one or more of their surfaces, similar to the pylon-type force transmitters 154. This allows for the measurement of mechanical strain caused by force applied to the surface of the force measurement apparatus 102.
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