Control of a passive prosthetic knee joint with adjustable damping

• US 7,731,759 B2
• Filed: 05/08/2007
• Issued: 06/08/2010
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: Ottobock SE & Co. KGaA
• Original Assignee: Otto Bock HealthCare GmbH (OTTO BOCK Holding GmbH & Company KG)
• Inventors: Pusch, Martin, Boiten, Herman, Zarling, Sven
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US12/300,131
• Publication Number:
  US 20090171468A1
• Time in Patent Office: 1,127 Days
• Field of Search: 623 39- 46, 623 24- 26
• US Class Current: 623/44
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2002/5033 for adjusting damping damping means A61F2002/5003
• CPC Class Codes: A61F 2002/5072 having spring elements spring-biased locking means A61F2002/30505; for implantable joints A61F2002/30565; other elastic means A61F2002/5007
• CPC Class Codes: A61F 2002/607 Lower legs
• CPC Class Codes: A61F 2002/6854 for locking or unlocking a joint
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• 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 2002/765 for measuring time or frequency
• CPC Class Codes: B25J 9/16 Programme controls programme controls in general G05B19/00, e.g. numerical pogramme controls G05B19/18; recording or playback systems G05B19/42
• CPC Class Codes: B25J 9/1628 characterised by the control loop

Abstract

The invention relates to the control of a passive prosthetic knee joint with adjustable damping in the direction of flexion such that a prosthetic unit attached to the knee joint can be adapted for climbing stairs.

Claims

1. A method for initiating and implementing a stair-climbing mode in a passive prosthetic knee joint connected to a prosthetic leg unit including a prosthetic foot comprising:

detecting a low-torque lift of the prosthetic foot;

initiating a lift phase, in which a flexion damping level of the knee joint is reduced to a level below that which is used for walking on level ground;

detecting a placement of the prosthetic foot; and

initiating a lowering phase, in which the flexion damping level is increased to a level above that which is used for walking on level ground.

2. The method of claim 1, wherein in the lowering phase, an extension damping level is increased to a level above that which is used for walking on level ground.

3. The method of claim 2, wherein the flexion damping are increased to maximum levels in the lowering phase.

4. The method of claim 1, wherein the flexion damping is reduced to a minimum level in the lift phase.

5. The method of claim 1 further comprising the step of, during the lowering phase, maintaining the flexion damping level until a straightened hip is detected.

6. The method of claim 1, further comprising the step of, during the lowering phase, detecting a knee angle and establishing the flexion damping level as a function of the detected knee angle.

7. The method of claim 1 wherein at least one of the detecting steps comprises the step of detecting an axial force along the prosthetic unit.

8. The method of claim 1 wherein an extension damping level is established during each of the lifting and lowering phases.

9. The method of claim 1 wherein the step of detecting the low torque lift comprises measuring a horizontal acceleration of the prosthetic foot and by detecting a bend in the knee joint.

10. The method of claim 1 wherein the step of detecting the low torque lift comprises detecting a torque at the front of the prosthetic foot.

11. The method of claim 1 wherein the step of detecting the placement of the foot comprises measuring an axial force measurement along the prosthetic unit.

12. The method of claim 1 wherein after initiating the lifting phase, a time controlled free extension is set.