Prosthetic hydraulic joint with accumulator and methods for controlling joint

Patent metadata

Field	Value
Publication number	US-9820871-B2
Application number	US-201213540388-A
Country	US
Kind code	B2
Filing date	Jul 2, 2012
Priority date	Jul 1, 2011
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A prosthetic foot assembly is disclosed. The assembly includes a pivoting ankle joint with a hydraulic system, a prosthetic foot connected to the distal side of the ankle joint, and, at the proximal side, the ankle joint includes a transducer with pyramid adaptor for attaching to a pylon. The ankle joint sensor provides data collection during the stance and optionally, the swing, phases of walking using, for example, strain gages and accelerometers. Also disclosed are methods for real-time feature extraction. Key parameters are captured to which are applied linear, fuzzy logic, neural net, or generic algorithms to determine current state (walking flat, uphill, downhill etc.) in real time and execute changes to the angle between the ankle and foot almost instantaneously based on those parameters.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for controlling a prosthetic ankle joint employing a processor and a sensor, the method comprising:
gathering gait data of a prosthetic ankle joint in real time;
determining if the prosthetic ankle joint is weight bearing;
if the prosthetic ankle joint is weight bearing, determining if a stance phase is qualified to be a true stance phase of a patient ambulating by dynamically comparing the gathered gait data to a set of recorded gait data while the patient is wearing the prosthetic ankle joint and ambulating;
if the stance phase is qualified to be a true stance phase, determining a ground slope or a speed of the patient, and dynamically changing an angular alignment of the prosthetic ankle joint a predetermined incremental amount based on the ground slope or speed, wherein dynamically changing the angular alignment comprises:
transferring hydraulic fluid between hydraulic chambers, the hydraulic chambers each comprising a piston in contact with a parabolic cam surface on a bottom base; and

if the prosthetic ankle joint is not weight bearing, locking or relaxing the ankle joint.

2. The method of claim 1 , further comprising collecting the set of recorded gait data, the recorded gait data being training gait data collected from the patient with a normal gait.

3. The method of claim 1 , further comprising collecting the set of recorded gait data, the recorded gait data being training gait data from the patient walking on a level ground and at a normal speed, and determining a home position for the ankle joint based on the level ground and normal speed.

4. The method of claim 3 , further comprising, when a level ground slope is detected, controlling the ankle joint at the home position.

5. The method of claim 3 , further comprising, when a normal speed is detected, controlling the ankle joint at the home position.

6. The method of claim 1 , further comprising collecting the set of recorded gait data, the recorded gait data being training gait data from a patient with a normal gait, comparing the training gait data to data that is collected from the qualified stance phase, and, based on the comparison, detecting the ground slope or speed.

7. The method of claim 6 , further comprising, when the ground slope is detected to be uphill, dorsiflexing the prosthetic ankle joint.

8. The method of claim 6 , further comprising, when the ground slope is detected to be downhill, plantarflexing the prosthetic ankle joint.

9. The method of claim 6 , further comprising, when the patient is detected to be walking slow, dorsiflexing the prosthetic ankle joint.

10. The method of claim 6 , further comprising, when the patient is detected to be walking fast, plantarflexing the prosthetic ankle joint.

11. The method of claim 1 , further comprising, if the stance phase is qualified to be a true stance phase, determining if the patient is ascending stairs or descending stairs.

12. The method of claim 1 , further comprising determining anterior moment and posterior moment during a stance phase, and comparing the anterior moment and posterior moment to the set of recorded gait data.

13. The method of claim 12 , further comprising detecting downhill when a maximum anterior moment is less than a maximum anterior moment of the training data and a maximum posterior moment is greater than a maximum posterior moment of the set of recorded gait data.

14. The method of claim 12 , further comprising detecting uphill when a maximum anterior moment is greater than a maximum anterior moment of the training data and a maximum posterior moment is less than a maximum posterior moment of the set of recorded gait data.

15. The method of claim 12 , further comprising detecting ascending stairs when an axial force is greater than an axial force of the set of recorded gait data and a posterior or anterior moment is greater than a posterior or anterior moment of the set of recorded gait data.

16. The method of claim 12 , further comprising detecting descending stairs when an axial force is greater than an axial force of the set of recorded gait data and a posterior or anterior moment is greater than a posterior or anterior moment of the set of recorded gait data.

17. The method of claim 1 , further comprising, when the ankle joint is not weight bearing, detecting if a keel angle is greater than a predetermined value and an anterior moment is greater than a predetermined value for a specified time period.

18. The method of claim 17 , further comprising, in response to detecting a keel angle is greater than a predetermined value and an anterior moment is greater than a predetermined value for a specified time period, locking the ankle joint.

19. The method of claim 17 , further comprising, in response to not detecting a keel angle is greater than a predetermined value and an anterior moment is greater than a predetermined value for a specified time period, relaxing the ankle joint.

20. The method of claim 19 , further comprising, when the ankle joint is relaxed, detecting at least one condition from the ankle joint is weight bearing, the ankle joint rate of motion exceeds a predetermined value, or the axial force rate of change exceeds a predetermined value, and, in response to detecting the one condition, moving the ankle to a home position determined from the set of recorded gait data.

21. The method of claim 1 , further comprising plantarflexing the ankle joint when a posterior moment is sensed during a stance phase.

22. The method of claim 1 , further comprising dorsiflexing the ankle joint when an anterior moment is sensed during a stance phase.

23. The method of claim 1 , further comprising determining if a swing phase is qualified to be a true swing phase of a patient ambulating, and, if the stance phase and swing phase are qualified to be a true stance phase and swing phase of a person ambulating, determining a ground slope or a speed of the patient.

24. The method of claim 23 , further comprising collecting the set of recorded gait data, the recorded gait data being training gait data from the patient with a normal gait, and comparing the training gait data to data that is collected when the ankle joint is weight bearing, and, based on the comparison, qualifying the stance and swing phase.

25. The method of claim 23 , further comprising collecting the set of recorded gait data, the recorded gait data being training gait data from a patient with a normal gait, comparing the training gait data to data that is collected from the qualified stance and swing phase, and, based on the comparison, detecting the ground slope or speed.

26. A method for controlling a prosthetic ankle joint employing a processor and a sensor, the method comprising:
gathering gait data of a prosthetic ankle joint in real time;
determining if the prosthetic ankle joint is weight bearing;
if the prosthetic ankle joint is weight bearing, determining if a stance phase is qualified to be a true stance phase of a patient ambulating by dynamically comparing the gathered gait data to a set of recorded gait data while the patient is wearing the prosthetic ankle joint and ambulating;
if the stance phase is qualified to be a true stance phase, determining a ground slope or a speed of the patient, and dynamically changing an angular alignment of the prosthetic an

Assignees

• Arabian Adam
• Boone David Alan
• Macomber Ben Gilbert
• Butel Tyler
• Lane Robert Dustin
• Bock Healthcare Gmbh

Inventors

• Arabian Adam
• Boone David Alan
• Macomber Ben Gilbert
• Butel Tyler
• Lane Robert Dustin

Classifications

• A61F2/70

  electrical · CPC title

• A61F2002/7625

  for measuring angular position · CPC title

• A61F2/6607 Primary

  Ankle joints · CPC title

• A61F2002/764

  for measuring acceleration · CPC title

• A61F2002/7645

  for measuring torque, e.g. hinge or turning moment, moment of force · CPC title