Force measurement system

• US 10,413,230 B1
• Filed: 03/09/2019
• Issued: 09/17/2019
• Est. Priority Date: 01/19/2013
• Status: Active Grant

• Current Assignee: Bertec Corporation
• Original Assignee: Bertec Corporation
• Inventors: Berme, Necip, Pitale, Jaswandi Tushar, Wang, Qian
• Primary Examiner(s): Amini, Javid A
• Application Number:
  US16/297,615
• Time in Patent Office: 192 Days
• Field of Search: 345633
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 3/032 Devices for presenting test symbols or characters, e.g. test chart projectors A61B3/036 takes precedence
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/1171 based on the shapes or appearances of their bodies or parts thereof
• CPC Class Codes: A61B 5/4023 Evaluating sense of balance
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7425 Displaying combinations of multiple images regardless of image source, e.g. displaying a reference anatomical image with a live image geometric transforms for image registration G06T3/14; enhancement using image fusion G06T5/50; algorithms for registration of images G06T7/30
• CPC Class Codes: A63F 2300/8082 Virtual reality
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/0334 Foot operated pointing devices
• CPC Class Codes: G06T 19/006 Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00

Abstract

A force measurement system is disclosed herein. The force measurement system includes a force measurement assembly configured to receive a subject thereon, at least one visual display device having an output screen, and one or more data processing devices operatively coupled to the force measurement assembly and the at least one visual display device. In one or more embodiments, the one or more data processing devices are configured to determine a presence of a measurement error resulting from a portion of the load from at least one portion of the body of the subject being applied to an external object rather than the intended top surface of the force measurement assembly.

Claims

1. A force measurement system, comprising:

a force measurement assembly configured to receive a subject, the force measurement assembly including;

a top surface for receiving at least one portion of the body of the subject; and

at least one force transducer, the at least one force transducer configured to sense one or more measured quantities and output one or more signals that are representative of forces and/or moments being applied to the top surface of the force measurement assembly by the subject;

a base assembly having a stationary portion and a displaceable portion, the force measurement assembly forming a part of the displaceable portion of the base assembly;

at least one actuator configured to rotate the force measurement assembly relative to the stationary portion of the base assembly about a transverse rotational axis;

at least one visual display device having an output screen, the at least one visual display device configured to display one or more scenes on the output screen so that the scenes are viewable by the subject; and

one or more data processing devices operatively coupled to the force measurement assembly and the at least one visual display device, the one or more data processing devices configured to receive the one or more signals that are representative of the forces and/or moments being applied to the top surface of the force measurement assembly by the subject, and to convert the one or more signals into output forces and/or moments, the one or more data processing devices further configured to determine a presence of a measurement error resulting from a portion of the load from the at least one portion of the body of the subject being applied to an external object rather than the intended top surface of the force measurement assembly.

2. The force measurement system according to claim 1, wherein the one or more data processing devices are configured to determine the presence of the measurement error by computing a maximum drop in the vertical component of the output force for a predetermined duration of time.

3. The force measurement system according to claim 1, wherein the one or more data processing devices are configured to determine the presence of the measurement error by computing an average drop in the vertical component of the output force for a predetermined duration of time.

4. The force measurement system according to claim 1, further comprising an external force sensor configured to measure a force exerted on the external object by the subject, the external force sensor being operatively coupled to the one or more data processing devices;

and

wherein the one or more data processing devices are configured to determine the presence of the measurement error by determining whether the force measured by the external force sensor is greater than a predetermined threshold value.

5. The force measurement system according to claim 1, wherein the external object on which the subject is exerting the force comprises (i) a safety harness worn by the subject to prevent the subject from falling, and/or (ii) a portion of a base of the force measurement system.

6. The force measurement system according to claim 5, wherein the one or more data processing devices are further configured to classify the type of action by the subject that results in the subject exerting the force on the external object.

7. The force measurement system according to claim 6, wherein the type of action by the subject that results in the subject exerting the force on the external object is selected from the group consisting of:

(i) pulling on a safety harness, (ii) stepping at least partially off the top surface of the force measurement assembly, and (iii) combinations thereof.

8. The force measurement system according to claim 1, wherein the at least one visual display device comprises a curved display screen or a plurality of flat display screens arranged or joined together in a concave arrangement so as to at least partially circumscribe the three sides of the torso of the subject.

9. The force measurement system according to claim 1, wherein the force measurement assembly is in the form of an instrumented treadmill.

10. The force measurement system according to claim 1, wherein the at least one actuator comprises a first actuator configured to rotate the force measurement assembly about the transverse rotational axis and a second actuator configured to translate the displaceable portion of the base assembly that includes the force measurement assembly.

11. The force measurement system according to claim 1, wherein the one or more data processing devices are further configured to generate an error notification on the output screen of the at least one visual display device when the one or more data processing devices determine the presence of the measurement error.

12. The force measurement system according to claim 11, wherein the one or more data processing devices are further configured to classify the type of action by the subject that results in the portion of the load being applied to the external object.

13. The force measurement system according to claim 12, wherein the error notification generated on the output screen of the at least one visual display device by the one or more data processing devices includes the classification of the type of action by the subject that results in the portion of the load being applied to the external object.

14. The force measurement system according to claim 1, wherein the visual display device is in the form of a head-mounted visual display device with an output screen, the output screen of the head-mounted visual display device being configured to partially circumscribe the head of the subject such that the subject becomes immersed in the simulated environment.

15. The force measurement system according to claim 1, wherein the visual display device is in the form of a head-mounted visual display device, the head-mounted visual display device comprising one of a virtual reality headset or an augmented reality headset.

16. The force measurement system according to claim 1, further comprising an external force sensor configured to measure a force exerted on the external object by the subject, the external object being the stationary portion of the base assembly, and the external force sensor being operatively coupled to the one or more data processing devices;

and

wherein the one or more data processing devices are configured to determine the presence of the measurement error by determining whether the force measured by the external force sensor is greater than a predetermined threshold value.

17. A force measurement system, comprising:

a force measurement assembly configured to receive a subject, the force measurement assembly including;

a top surface for receiving at least one portion of the body of the subject; and

at least one force transducer, the at least one force transducer configured to sense one or more measured quantities and output one or more signals that are representative of forces and/or moments being applied to the top surface of the force measurement assembly by the subject;

a base assembly having a stationary portion and a displaceable portion, the top surface of the force measurement assembly forming a part of the displaceable portion of the base assembly;

at least one actuator configured to displace the top surface of the force measurement assembly relative to the stationary portion of the base assembly;

at least one visual display device having an output screen, the at least one visual display device configured to display one or more scenes on the output screen so that the scenes are viewable by the subject; and

one or more data processing devices operatively coupled to the force measurement assembly and the at least one visual display device, the one or more data processing devices configured to receive the one or more signals that are representative of the forces and/or moments being applied to the top surface of the force measurement assembly by the subject, and to convert the one or more signals into output forces and/or moments, the one or more data processing devices further configured to determine a presence of a measurement error resulting from a portion of the load from the at least one portion of the body of the subject being applied to an external object rather than the intended top surface of the force measurement assembly, the one or more data processing devices additionally configured to determine the presence of the measurement error by computing a maximum drop or an average drop in the vertical component of the output force for a predetermined duration of time.

18. A force measurement system, comprising:

a force measurement assembly configured to receive a subject, the force measurement assembly including;

a top surface for receiving at least one portion of the body of the subject; and

at least one force transducer, the at least one force transducer configured to sense one or more measured quantities and output one or more signals that are representative of forces and/or moments being applied to the top surface of the force measurement assembly by the subject;

at least one visual display device having an output screen, the at least one visual display device configured to display one or more scenes on the output screen so that the scenes are viewable by the subject; and

one or more data processing devices operatively coupled to the force measurement assembly and the at least one visual display device, the one or more data processing devices configured to receive the one or more signals that are representative of the forces and/or moments being applied to the top surface of the force measurement assembly by the subject, and to convert the one or more signals into output forces and/or moments, the one or more data processing devices further configured to determine a presence of a measurement error resulting from a portion of the load from the at least one portion of the body of the subject being applied to an external object rather than the intended top surface of the force measurement assembly, the one or more data processing devices additionally configured to generate an error notification on the output screen of the at least one visual display device when the one or more data processing devices determine the presence of the measurement error.

19. The force measurement system according to claim 18, wherein the one or more data processing devices are further configured to classify the type of action by the subject that results in the portion of the load being applied to the external object;

and

wherein the error notification generated on the output screen of the at least one visual display device by the one or more data processing devices includes the classification of the type of action by the subject that results in the portion of the load being applied to the external object.

20. The force measurement system according to claim 18, wherein the force measurement assembly is in the form of an instrumented treadmill, and wherein the force measurement system further comprises a motion base disposed underneath the instrumented treadmill, the motion base configured to displace the instrumented treadmill in one or more directions.

21. The force measurement system according to claim 18, further comprising a base assembly having a stationary portion and a displaceable portion, the top surface of the force measurement assembly forming a part of the displaceable portion of the base assembly, and at least one actuator configured to displace the top surface of the force measurement assembly relative to the stationary portion of the base assembly.

22. The force measurement system according to claim 18, wherein the one or more data processing devices are configured to determine the presence of the measurement error by computing a maximum drop or an average drop in the vertical component of the output force for a predetermined duration of time.