Control System and Method for Non-Gait Ankle and Foot Motion in Human Assistance Device

• US 20170071762A1
• Filed: 11/02/2016
• Published: 03/16/2017
• Est. Priority Date: 02/17/2012
• Status: Active Grant

• Current Assignee: Ossur Iceland ehf
• Original Assignee: SpringActive, Inc.
• Inventors: Wheeler, Chase, Holgate, Matthew A.
• Granted Patent: US 10,307,271 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61F 2/60 Artificial legs or feet or parts thereof
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2/76 Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/762 for measuring dimensions, e.g. a distance
• CPC Class Codes: A61F 2002/7625 for measuring angular position
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/764 for measuring acceleration
• CPC Class Codes: A61F 2002/7645 for measuring torque, e.g. hinge or turning moment, moment of force
• CPC Class Codes: A61F 5/02 Orthopaedic corsets arm-rests for use as writing aids B43L15/00

Abstract

A human assistance device has a rate gyro, first accelerometer, and second accelerometer disposed on a mobile body for sensing a physical state of the mobile body to provide a physical state measurement. The human assistance device can be a prosthetic, orthotic, and robotic device. An ATAN 2 function is performed on an output of the first accelerometer and an output of the second accelerometer. An output of the rate gyro and an output of the ATAN2 function is filtered to provide a filtered physical state measurement. The filtered physical state measurement is applied to a reference function to generate a reference command to control a non-gait motion of an actuator in the human assistance device. The reference command controls the human assistance device, for example to provide a shifting foot position while seated, with a natural, biological motion, without an artificial or mechanical appearance.

Claims

1. A method of controlling a human assistance device, comprising:

disposing a rate gyro, first accelerometer, and second accelerometer on a mobile body for sensing a physical state of the mobile body to provide a physical state measurement;

performing an ATAN2 function on an output of the first accelerometer and an output of the second accelerometer;

filtering an output of the rate gyro and an output of the ATAN2 function to provide a filtered physical state measurement;

providing a reference function based on a non-gait activity; and

applying the filtered physical state measurement to the reference function to generate a reference command to control a non-gait motion of the human assistance device.

2. The method of claim 1, wherein the filtering is implemented as A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A₁ is a calibration coefficient, θ

_PREV is a previous θ

_T, At is rate of time change, θ

_s is the output of the rate gyro, and β

is the output of the ATAN2 function.

3. The method of claim 1, wherein the reference command controls an actuator in the human assistance device.

4. The method of claim 3, further including applying a signal representative of a position of the actuator to the reference function to generate the reference command.

5. The method of claim 1, further including:

measuring an ankle moment;

applying a gain to the ankle moment; and

summing the ankle moment after gain with an output of the reference function to generate the reference command.

6. The method of claim 5, wherein the gain is implemented as A₂ cos

7. A method of controlling a human assistance device, comprising:

disposing a plurality of sensors on a mobile body to measure a physical state of the mobile body and obtain a physical state measurement;

filtering the physical state measurement;

providing a reference function based on a non-gait activity; and

applying the filtered physical state measurement to the reference function to generate a reference command to control a non-gait motion of the human assistance device.

8. The method of claim 7, wherein the sensors include a rate gyro, first accelerometer, and second accelerometer.

9. The method of claim 8, further including performing an ATAN2 function on an output of the first accelerometer and an output of the second accelerometer, wherein filtering the physical state measurement includes filtering an output of the rate gyro and an output of the ATAN2 function.

10. The method of claim 9, wherein the filtering is implemented as A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A₁ is a calibration coefficient, θ

_PREV is a previous θ

_T, At is rate of time change, {dot over (θ

)}_s is the output of the rate gyro, and β

is the output of the ATAN2 function.

11. The method of claim 7, wherein the reference command controls an actuator in the human assistance device, and a signal representative of a position of the actuator is applied to the reference function to generate the reference command.

12. The method of claim 7, further including:

measuring an ankle moment;

applying a gain to the ankle moment; and

summing the ankle moment after gain with an output of the reference function to generate the reference command.

13. The method of claim 12, wherein the gain is implemented as A₂ cos

14. A method of controlling a human assistance device, comprising:

sensing a physical state of a mobile body to provide a physical state measurement;

filtering the physical state measurement;

providing a reference function based on a non-gait activity; and

applying the filtered physical state measurement to the reference function to generate a reference command to control a non-gait motion of the human assistance device.

15. The method of claim 14, further including disposing a rate gyro, first accelerometer, and second accelerometer on the mobile body for sensing the physical state of the mobile body.

16. The method of claim 15, further including performing an ATAN2 function on an output of the first accelerometer and an output of the second accelerometer, wherein filtering the physical state measurement includes filtering an output of the rate gyro and an output of the ATAN2 function.

17. The method of claim 16, wherein the filtering is implemented as A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A₁ is a calibration coefficient, A_PREV is a previous θ

_T, Δ

t is rate of time change, {dot over (θ

)}_s is the output of the rate gyro, and β

is the output of the ATAN2 function.

18. The method of claim 14, wherein the reference command controls an actuator in the human assistance device, and a signal representative of a position of the actuator is applied to the reference function to generate the reference command.

19. The method of claim 14, further including:

measuring an ankle moment;

applying a gain to the ankle moment; and

summing the ankle moment after gain with an output of the reference function to generate the reference command.

20. The method of claim 19, wherein the gain is implemented as A₂ cos

21. A human assistance device, comprising:

a prosthetic limb device;

a plurality of sensors coupled to the prosthetic limb device; and

a control system coupled to the prosthetic limb device, wherein the control system is configured to obtain a physical state measurement from the sensors and produce a reference command to control a non-gait activity of the prosthetic limb device.

22. The human assistance device of claim 21, wherein the sensors include a rate gyro, first accelerometer, and second accelerometer.

23. The human assistance device of claim 22, further including:

means for performing an ATAN2 function on an output of the first accelerometer and an output of the second accelerometer; and

a filter having a first input coupled to an output of the rate gyro, a second input coupled to an output of the means for performing the ATAN2 function, and an output providing a filtered physical state measurement.

24. The human assistance device of claim 23, wherein the filter is implemented as A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A₁ is a calibration coefficient, θ

_PREV is a previous θ

_T, Δ

t is rate of time change, {dot over (θ

)}_s is the output of the rate gyro, and β

is the output of the ATAN2 function.

25. The human assistance device of claim 21, further including:

means for measuring an ankle moment;

means for applying a gain to the ankle moment; and

means for summing the ankle moment after gain with an output of the reference function to generate the reference command.