Systems and methods for adjusting the angle of a prosthetic ankle based on a measured surface angle

• US 20060224246A1
• Filed: 03/01/2006
• Published: 10/05/2006
• Est. Priority Date: 02/12/2004
• Status: Active Grant

• Current Assignee: Ossur hf
• Original Assignee: Arion Banki Hf
• Inventors: MacDonald, Paul, Ragnarsdottir, Heidrun G., Jonsson, Helgi, Clausen, Arinbjorn V.
• Granted Patent: US 7,637,959 B2
• Time in Patent Office: Days
• US Class Current: 623/24
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2002/5018 for adjusting angular orientation
• CPC Class Codes: A61F 2002/5073 Helical springs, e.g. having at least one helical spring
• CPC Class Codes: A61F 2002/6642 Heels
• CPC Class Codes: A61F 2002/6685 S-shaped
• CPC Class Codes: A61F 2002/701 operated by electrically controlled means, e.g. solenoids or torque motors
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/705 Electromagnetic data transfer for implantable prostheses A61F2250/0002
• 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

Abstract

System and method for adjusting the angle of a prosthetic ankle are disclosed. In one example, the system, such as an actuated prosthetic ankle joint, detects the surface angle and actively adjusts the members of the ankle to a preferred angle according to the respective slope of the incline/decline.

Claims

1. A method for operating a prosthetic ankle worn by a user, comprising:

providing a prosthetic ankle comprising a foot unit and a lower limb member, the foot unit and lower limb member configured to rotate at about a location of a natural human ankle;

detecting an incline or decline of a surface while the user moves with the prosthetic ankle; and

adjusting an angle between the foot unit and the lower limb member based on the detected incline or decline.

2. The method of claim 1, wherein the angle between the foot unit and lower limb member is adjusted with an actuator.

3. The method of claim 1, wherein the angle between the foot unit and lower limb member decreases between about 0 and 30 degrees when adjusting to an incline.

4. The method of claim 1, wherein the angle between the foot unit and lower limb member increases between about 0 and 30 degrees when adjusting to a decline.

5. The method of claim 1, wherein detecting an incline or decline of a surface comprises measuring an angle of incline or decline.

6. The method of claim 1, wherein the incline or decline of a surface is detected using a sensor provided on the prosthetic ankle.

7. A method for operating a prosthetic ankle worn by a user, comprising:

providing a prosthetic ankle comprising a foot unit and a lower limb member, the foot unit and lower limb member configured to rotate at about a location of a natural human ankle;

measuring a terrain variable upon which the user moves with the prosthetic ankle; and

adjusting an angle between the foot unit and the lower limb member based on the measured terrain variable.

8. The method of claim 7, wherein measuring a terrain variable comprises measuring an incline or decline of a walking surface.

9. The method of claim 7, wherein measuring a terrain variable comprises detecting whether the user is ascending or descending stairs.

10. The method of claim 7, wherein the angle between the foot unit and lower limb member is adjusted with an actuator.

11. The method of claim 7, wherein the terrain variable is measured using a sensor provided on the prosthetic ankle.

12. A method for operating a prosthetic ankle worn by a user, comprising:

providing a prosthetic ankle comprising a foot unit and a lower limb member, the foot unit and lower limb member configured to rotate at about a location of a natural human ankle;

measuring a surface angle of a surface upon which the user moves with the prosthetic ankle;

calculating a desired angle between the foot unit and the lower limb member for moving upon the surface, wherein the calculation is based at least in part on the measured surface angle; and

adjusting an angle between the foot unit and the lower limb member to the desired angle.

13. The method of claim 12, wherein the measured surface angle is positive for an inclined surface and negative for a declined surface.

14. The method of claim 12, wherein the desired angle is a percentage of the measured surface angle for at least one of the surface angle being positive or negative.

15. The method of claim 14, wherein the desired angle is a percentage of the measured surface angle when the measured surface angle is positive for an inclined surface.

16. The method of claim 12, wherein the desired angle decreases in dorsiflexion from an angle of the prosthetic ankle in a neutral position when the measured surface angle is positive for an inclined surface, and the desired angle increases in plantarflexion from an angle of the prosthetic ankle in a neutral position when the measured surface angle is negative for a declined surface.

17. The method of claim 16, wherein an amount that the desired angle decreases in dorsiflexion is larger relative to the measured surface angle of the inclined surface, than an amount that the desired angle increases in plantarflexion relative to the measured surface angle of the declined surface.

18. The method of claim 17, wherein the amount that the desired angle decreases in dorsiflexion is about 100% of the measured surface angle of the inclined surface, and the amount that the desired angle decreases in plantarflexion is between about 10% and 100% of the measured surface angle of the declined surface.

19. The method of claim 18, wherein the amount that the desired angle decreases in plantarflexion increases nonlinearly as the measured surface angle of the declined surface increases.