Control system and method for non-gait ankle and foot motion in human assistance device

• US 10,307,271 B2
• Filed: 11/02/2016
• Issued: 06/04/2019
• Est. Priority Date: 02/17/2012
• Status: Active Grant

• Current Assignee: Ossur Iceland ehf
• Original Assignee: Ossur Iceland ehf
• Inventors: Holgate, Matthew A., Wheeler, Chase
• Primary Examiner(s): Woznicki, Jacqueline
• Application Number:
  US15/341,817
• Publication Number:
  US 20170071762A1
• Time in Patent Office: 944 Days
• 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 ATAN2 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 of the human assistance device for sensing a physical state of the mobile body to provide a physical state measurement;

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

filtering electronically an output of the rate gyro and an output of the ATAN2 function using a controller of the human assistance device to provide a filtered physical state measurement, wherein the filtering is implemented according to A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A1 is a calibration coefficient, θ

_PREV is a previous output of the filtering, Δ

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

)}_s, {dot over (θ

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

is the output of the ATAN2 function;

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 using the controller to control a non-gait motion of the human assistance device.

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

3. The method of claim 2, further including applying a signal representative of a position of the actuator to the reference function to generate the reference command.

4. The method of claim 1, further including:

measuring an ankle moment, wherein the human assistance device comprises an ankle prosthesis;

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.

5. The method of claim 4, wherein the gain is implemented as A₂ cos

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

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

filtering electronically the physical state measurement from the sensors using a controller of the human assistance device to provide a filtered physical state measurement, wherein the filtering is implemented according to A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A1 is a calibration coefficient, θ

_PREV is a previous output of the filtering, Δ

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

)}_s, {dot over (θ

)}_s is an output of a rate gyro on the mobile body, and β

is an output of an ATAN2 function;

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 using the controller to control a non-gait motion of the human assistance device.

7. The method of claim 6, wherein the sensors include the rate gyro, a first accelerometer, and a second accelerometer.

8. The method of claim 7, further including performing the ATAN2 function based 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.

9. The method of claim 6, 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.

10. The method of claim 6, further including:

measuring an ankle moment, wherein the human assistance device comprises an ankle prosthesis;

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.

11. The method of claim 10, wherein the gain is implemented as A₂ cos

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

sensing a physical state of a mobile body of the human assistance device by providing a physical state measurement of the physical state;

filtering electronically the physical state measurement of the physical state of the mobile body using a controller of the human assistance device to provide a filtered physical state measurement, wherein the filtering is implemented according to A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)+(1−

A₁)*β

, where A1 is a calibration coefficient, θ

_PREV is a previous output of the filtering, Δ

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

)}_s, {dot over (θ

)}_s is an output of a rate gyro on the mobile body, and β

is an output of an ATAN2 function;

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 using the controller to control a non-gait motion of the human assistance device.

13. The method of claim 12, further including disposing the rate gyro, a first accelerometer, and a second accelerometer on the mobile body for sensing the physical state of the mobile body.

14. The method of claim 13, further including performing an ATAN2 function based 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.

15. The method of claim 12, 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.

16. The method of claim 12, further including:

measuring an ankle moment, wherein the human assistance device comprises an ankle prosthesis;

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.

17. The method of claim 16, wherein the gain is implemented as A₂ cos

18. 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 and to apply an electronic filter that is implemented according to A₁*(θ

_PREV+{dot over (θ

)}_s*Δ

t)±

(1−

A₁)*β

, where A1 is a calibration coefficient, θ

_PREV is a previous output of the filtering, Δ

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

)}_s, {dot over (θ

)}_s is an output of a rate gyro on the mobile body, and β

is an output of an ATAN2 function.

19. The human assistance device of claim 18, wherein the sensors include the rate gyro, a first accelerometer, and a second accelerometer.

20. The human assistance device of claim 19, wherein the control system is configured to perform the ATAN2 function based on an output of the first accelerometer and an output of the second accelerometer;

and wherein the electronic filter has a first input coupled to an output of the rate gyro, a second input coupled to the output of the ATAN2 function, and an output providing a filtered physical state measurement.

21. The human assistance device of claim 18, further including wherein the control system is configured to:

measure an ankle moment, wherein the prosthetic limb device comprises an ankle prosthesis;

apply a gain to the ankle moment; and

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