Sensing system and method for motion-controlled foot unit

• US 20070050045A1
• Filed: 09/01/2005
• Published: 03/01/2007
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: Ossur hf
• Original Assignee: Ossur hf
• Inventors: Lecomte, Christophe, Sigfusson, Larus, Clausen, Arinbjorn
• Granted Patent: US 7,531,006 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
• 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

A system and method for sensing movement of a device associated with a limb. In one example, a prosthetic or orthotic system includes a sensor assembly configured to measure movement of a component of the system in a single direction while substantially isolating negative effects of forces and/or loads in other directions. For instance, the sensor assembly may be advantageously coupled to a pivot assembly configured to substantially mimic a natural ankle joint. The sensor assembly may monitor rotation of a foot unit about an axis of a pivot pin of the pivot assembly and disregard other movements and/or forces. For example, the sensor assembly may include a potentiometer that detects rotation of an associated elongated bellow portion about the axis, wherein the bellow portion includes a plurality of ridges configured to substantially eliminate effects of radial and/or axial forces.

Claims

1. A system for sensing a rotational movement of a lower-limb prosthetic device, the system comprising:

a prosthetic foot;

an attachment member having an upper end and a lower end;

a pivot assembly rotatably coupling the lower end of the attachment member to the prosthetic foot to allow for rotation of the prosthetic foot about a pivot axis extending through the pivot assembly, wherein the pivot assembly is configured to substantially mimic a natural ankle joint; and

a sensor assembly coupled to the pivot assembly and configured to detect the rotation of the prosthetic foot about the pivot axis, wherein at least a portion of the sensor assembly is configured to rotate about the pivot axis and is securely positioned along the pivot axis to substantially eliminate other movement.

2. The system of claim 1, wherein the sensor assembly comprises a displacement measurement sensor configured to output a signal indicative of the rotation of the rotatable portion of the sensor assembly.

3. The system of claim 2, wherein the displacement measurement sensor comprises a potentiometer.

4. The system of claim 2, wherein the rotatable portion of the sensor assembly comprises an elongated body that substantially extends along the pivot axis.

5. The system of claim 4, wherein the rotatable portion of the sensor assembly comprises a bellow portion.

6. The system of claim 5, wherein the bellow portion is configured to at least partially fit within a hollow pivot pin substantially extending along the pivot axis.

7. The system of claim 6, wherein the bellow portion comprises a plurality of ridges configured to limit movement of the bellow portion to rotation about the pivot axis.

8. A system for sensing a rotational movement of a device associated with a limb, the system comprising:

a foot unit;

an attachment member having an upper end and a lower end;

a pivot assembly rotatably coupling the lower end of the attachment member to the foot unit to allow for rotation of the foot unit about an axis extending through the pivot assembly, wherein the pivot assembly is configured to substantially mimic a natural ankle joint; and

a sensor assembly coupled to the pivot assembly and configured to detect the rotation of the foot unit about the axis and to substantially neglect axial and radial movement of the foot unit with respect to the axis.

9. The system of claim 8, wherein the sensor assembly further comprises a potentiometer.

10. The system of claim 9, wherein the sensor assembly further comprises an elongated bellow portion coupled to the potentiometer, wherein the elongated bellow portion substantially extends along the axis.

11. The system of claim 10, wherein the elongated bellow portion substantially restricts movement to rotation about the axis.

12. The system of claim 10, wherein the pivot assembly comprises a cylindrical pivot pin extending along the axis and configured to house at least a portion of the elongated bellow portion.

13. The system of claim 8, wherein the pivot assembly comprises a housing and a ball joint movable within the housing.

14. The system of claim 13, wherein the housing restricts movement of the ball joint to rotation about the axis.

15. The system of claim 8, wherein the foot unit comprises at least one of a prosthesis and an orthosis.

16. The system of claim 8, further comprising an actuator configured to adjust the attachment member and the foot unit about the pivot assembly.

17. The system of claim 16, wherein the actuator is configured to actively adjust an angle between the attachment member and the foot unit.

18. A system for sensing a rotational movement of a device associated with a lower limb, the system comprising:

a foot means for contacting a ground surface;

a means for attaching the foot means to a patient;

a means for pivotably coupling the foot means to a lower end of the means for attaching to allow for rotation of the foot means about an axis extending through the means for pivotably coupling, wherein the means for pivotably coupling substantially mimics an ankle joint; and

a means for sensing coupled to the means for pivotably coupling, the means for sensing further configured to detect the rotation of the foot means about the axis and to substantially neglect axial and radial movement of the foot means with respect to the axis.

19. The system of claim 18, wherein the means for sensing comprises a potentiometer.

20. The system of claim 19, wherein the means for sensing comprises an elongated bellow portion coupled to the potentiometer, wherein the elongated bellow portion is configured to restrict movement of the foot means to rotation about the pivot axis.