TERRAIN ADAPTIVE POWERED JOINT ORTHOSIS

• US 20120259431A1
• Filed: 01/23/2012
• Published: 10/11/2012
• Est. Priority Date: 01/21/2011
• Status: Active Grant

• Current Assignee: Otto Bock HealthCare LP (Nader Holding GmbH & Co. KG)
• Original Assignee: BionX Medical Technologies, Inc. (Ottobock SE & Co. KGaA)
• Inventors: Han, Zhixiu, Weber, Jeff A., Barnhart, Christopher E., Herr, Hugh M., Casler, Richard J. Jr., Williams, Christopher
• Granted Patent: US 9,687,377 B2
• Time in Patent Office: Days
• US Class Current: 623/24
• CPC Class Codes: A61F 5/0125 the device articulating around a single pivot-point
• CPC Class Codes: A61H 1/024 Knee A61H1/0255 takes precedence
• CPC Class Codes: A61H 2003/001 on steps or stairways
• CPC Class Codes: A61H 2201/1642 Holding means therefor
• CPC Class Codes: A61H 2201/165 Wearable interfaces
• CPC Class Codes: A61H 2201/5007 computer controlled
• CPC Class Codes: A61H 2201/5064 Position sensors
• CPC Class Codes: A61H 2201/5084 Acceleration sensors
• CPC Class Codes: A61H 2201/5097 wireless
• CPC Class Codes: A61H 2205/10 Leg
• CPC Class Codes: A61H 2205/102 Knee
• CPC Class Codes: A61H 3/00 Appliances for aiding patients or disabled persons to walk about apparatus for helping babies to walk A47D13/04 ; applying electrical currents by contact electrodes for stimulating motor muscles, e.g. walking assistance A61N1/36003

Abstract

A powered device augments a joint function of a human during a gait cycle using a powered actuator that supplies an augmentation torque, an impedance, or both to a joint. A controller estimates terrain slope and modulates the augmentation torque and the impedance according to a phase of the gait cycle and the estimated terrain slope to provide at least a biomimetic response. The controller may also modulate a joint equilibrium. Accordingly, the device is capable of normalizing or augmenting human biomechanical function, responsive to a wearer'"'"'s activity, regardless of speed and terrain, and can be used, for example, as a knee orthosis, prosthesis, or exoskeleton.

Claims

33. A powered human augmentation device for assisting a person walking on a surface, the device comprising:

a powered actuator for supplying to a joint at least one of an augmentation torque and an impedance comprising a linear spring component and a damping component; and

a controller for (i) determining a phase of a gait cycle, (ii) estimating within the gait cycle a slope of the surface, and (iii) modulating the augmentation torque and the impedance based on the phase of the gait cycle and the estimated slope to provide at least a biomimetic response.

1. A method for assisting a person walking on a surface with a powered human augmentation device including a controller, the method comprising the steps of:

determining a phase of a gait cycle;

estimating within the gait cycle, a slope of the surface;

supplying to a joint at least one of an augmentation torque and an impedance comprising a linear spring component and a damping component; and

modulating the augmentation torque and the impedance based on the phase of the gait cycle and the estimated slope to provide at least a biomimetic response.

2. The method of claim 1, wherein the estimated slope is indicative of a walking mode such that level-ground walking mode corresponds to a substantially zero slope, downslope walking mode corresponds to a negative slope, and upslope walking mode corresponds to a positive slope.

3. The method of claim 2, wherein the downslope walking mode comprises descending stairs and the upslope walking mode comprises ascending stairs.

4. The method of claim 1, wherein the joint is a knee.

5. The method of claim 1 further comprising estimating walking speed, wherein at least one of the augmentation torque and the impedance is based on the estimated walking speed.

6. The method of claim 1, wherein if the phase of the gait cycle is determined to be one of early stance and mid stance and the estimated slope is substantially zero, the impedance is modulated such that contribution of the linear spring component to the modulated impedance is greater than contribution of the damping component.

7. The method of claim 1, wherein if the phase of the gait cycle is determined to be one of early stance and mid stance and the estimated slope is negative, the impedance is modulated such that contribution of the damping component is increased substantially compared to contribution thereof if slope is estimated to be substantially zero.

8. The method of claim 7, wherein modulating comprises varying the damping component according to the negative slope.

9. The method of claim 1, wherein

the augmentation torque comprises a non-conservative propulsive torque;

and

if the phase of the gait cycle is determined to be one of early stance and mid stance and the estimated slope is positive, providing the non-conservative propulsive torque such that the modulated augmentation torque is greater than the modulated augmentation torque applied if the slope is estimated to be substantially zero.

10. The method of claim 1, wherein if the phase of the gait cycle is determined to be late stance, the augmentation torque is modulated to correspond to a reflex torque that is related to the estimated slope.

11. The method of claim 1 further comprising the step of modeling, during a swing phase of the gait cycle, a joint equilibrium as a second-order response to a joint-position goal to be achieved prior to a next phase of the gait cycle.

12. The method of claim 11 further comprising the step of determining if the joint is substantially fully flexed, during a swing phase of the gait cycle, wherein modulating comprises adjusting both the augmentation torque and the impedance to be substantially zero, if the joint is determined to be substantially fully flexed.

13. The method of claim 11, wherein if the phase of the gait cycle is determined to be early swing, the augmentation torque is modulated according to the joint-equilibrium model such that a joint equilibrium corresponds to the joint-position goal.

14. The method of claim 11, wherein if the phase of the gait cycle is determined to be early swing, the impedance is modulated according to the joint-equilibrium model such that a joint equilibrium corresponds to the joint-position goal.

15. The method of claim 1, wherein estimating the slope comprises kinematically reconstructing a path of the joint within the gait cycle.

16. The method of claim 15 further comprising the steps of:

kinematically reconstructing a path of another joint within the gait cycle; and

associating the path of the other joint with the path of the joint to estimate the slope.

17. The method of claim 15, wherein the kinematic reconstruction comprises computing a pose and an origin of a co-ordinate frame associated with a link connected to at least one of the joint and another joint proximal to the joint.

18. The method of claim 17, wherein computing the pose comprises creating a homogeneous transformation of the co-ordinate frame.

19. The method of claim 18, wherein the homogeneous transformation comprises:

a 3×

1 vector defining an origin of the co-ordinate frame; and

a 3×

3 matrix comprising unit vectors of the co-ordinate frame.

20. The method of claim 17, wherein at least one point within the co-ordinate frame corresponds to a link connected to at least one of the joint and another joint proximal to the joint.

21. The method of claim 20, wherein the another joint is an ankle joint and the at least one point is at least one of a distal end and a proximal end of a tibia connected to the ankle.

22. The method of claim 1, wherein the augmentation torque is modulated according to a positive-force feedback.

23. The method of claim 22, wherein the augmentation torque modulated according to the positive-force feedback, in combination with a natural joint torque supplied by the human, approximates at least a normal joint torque.

24. The method of claim 22, wherein the positive-force feedback comprises a gain and an exponent.

25. The method of claim 24, wherein modulating comprises adjusting at least one of the gain and the exponent according to at least one of the estimated slope and walking speed.

26. The method of claim 1, wherein the augmentation torque is modulated according to a scaling factor.

27. The method of claim 1 further comprising the step of attenuating the augmentation torque to be applied according to a protocol.

28. The method of claim 1, wherein the augmentation torque is supplied in addition to natural joint torque supplied by the person to achieve at least a pre-determined total joint torque response.

29. The method of claim 1, wherein modulating comprises applying a closed-loop torque control at the joint.

30. The method of claim 29 further comprising:

modeling the joint torque; and

determining the phase of the gait cycle based on the joint torque model.

31. The method of claim 1, wherein the augmentation torque, the impedance, and a joint equilibrium are modulated in order to achieve at least a target walking speed.

32. The method of claim 1, wherein the augmentation torque, the impedance, and a joint equilibrium are modulated in order to substantially achieve a metabolic economy in accordance with a normative reference across at least one of walking speed and terrain.

34. The device of claim 33, wherein the estimated slope is indicative of a walking mode such that level-ground walking mode corresponds to a substantially zero slope, downslope walking mode corresponds to a negative slope, and upslope walking mode corresponds to a positive slope.

35. The method of claim 34, wherein the downslope walking mode comprises descending stairs and the upslope walking mode comprises ascending stairs.

36. The device of claim 33, wherein the joint is a knee.

37. The device of claim 33, wherein the controller is adapted to estimate walking speed, and at least one of the augmentation torque and the impedance is based on the estimated walking speed.

38. The device of claim 33, wherein if the controller determines the phase of the gait cycle to be one of early stance and mid stance and the estimated slope is substantially zero, the powered actuator is adapted to provide the modulated impedance such that contribution of the linear spring component to the modulated impedance is greater than contribution of the damping component.

39. The device of claim 33, wherein if the controller determines the phase of the gait cycle to be one of early stance and mid stance and the estimated slope is negative, the powered actuator is adapted to provide the modulated impedance such that contribution of the damping component is increased substantially compared to contribution thereof if slope is estimated to be substantially zero.

40. The method of claim 7, wherein the controller is adapted to modulate the damping component according to the negative slope.

41. The device of claim 33, wherein

the augmentation torque comprises a non-conservative propulsive torque;

and

if the controller determines the phase of the gait cycle to be one of early stance and mid stance and the estimated slope is positive, the powered actuator is adapted to provide the non-conservative propulsive torque such that the modulated augmentation torque is greater than the modulated augmentation torque applied if the slope is estimated to be substantially zero.

42. The device of claim 33, wherein if the controller determines the phase of the gait cycle to be late stance, the powered actuator is adapted to provide the modulated augmentation torque such that the modulated augmentation torque corresponds to a reflex torque that is related to the estimated slope.

43. The device of claim 33, wherein the controller is adapted to model, during a swing phase of the gait cycle, a joint equilibrium as a second-order response to a joint-position goal to be achieved prior to a next phase of the gait cycle.

44. The device of claim 43 further comprising a joint angle sensor to provide a joint angle signal to the controller, wherein if the controller determines, based on the joint angle signal, that the joint is substantially fully flexed, the powered actuator is adapted to adjust both the augmentation torque and the impedance to be substantially zero, during a swing phase of the gait cycle.

45. The device of claim 43, wherein if the controller determines the phase of the gait cycle to be early swing, the augmentation torque is modulated according to the joint-equilibrium model such that a joint equilibrium corresponds to the joint-position goal.

46. The device of claim 43, wherein if the controller determines the phase of the gait cycle to be early swing, the impedance is modulated according to the joint-equilibrium model such that a joint equilibrium corresponds to the joint-position goal.

47. The device of claim 33 further comprising an inertial measurement unit (IMU), wherein the controller is adapted to kinematically reconstruct a path of the joint within the gait cycle based on a signal from the IMU, and to estimate the slope based on the kinematic reconstruction.

48. The device of claim 47, wherein the IMU comprises at least one of an accelerometer and a gyroscope.

49. The device of claim 47, wherein the IMU comprises a first set of sensors associated with the joint and a second set of sensors associated with another joint, and the controller is adapted to:

kinematically reconstruct a path of the other joint within the gait cycle based on signals from the second set of sensors; and

associate the path of the other joint with the path of the joint to estimate the slope.

50. The device of claim 33, wherein the augmentation torque is modulated according to a positive-force feedback.

51. The device of claim 50, wherein the augmentation torque modulated according to the positive-force feedback, in combination with a natural joint torque supplied by the human, approximates at least a normal joint torque.

52. The device of claim 50, wherein the positive-force feedback comprises a gain and an exponent.

53. The device of claim 52, wherein modulating comprises adjusting at least one of the gain and the exponent according to at least one of the estimated slope and walking speed.

54. The device of claim 33, wherein the controller is adapted to modulate the augmentation torque according to a scaling factor.

55. The device of claim 33 further comprising a communication interface for receiving a protocol, and the controller is adapted to attenuate the augmentation torque according to the received protocol.

56. The device of claim 33, wherein the augmentation torque is supplied in addition to natural joint torque supplied by the person to achieve at least a pre-determined total joint torque response.

57. The device of claim 33, wherein the controller is adapted to apply a closed-loop torque control at the joint.

58. The device of claim 57, wherein the controller is adapted to:

model the joint torque; and

determine the phase of the gait cycle based on the joint torque model.

59. The device of claim 33, wherein the powered actuator comprises a series-elastic actuator.

60. The device of claim 59, wherein the series-elastic actuator comprises a transverse-flux motor.

61. The device of claim 59, wherein the series-elastic actuator comprises a bilateral spring and a cable drive.

62. The device of claim 59, wherein the series-elastic actuator comprises a unidirectional spring.

61-1. The device of claim 59, wherein the series-elastic actuator comprises a buckled beam.