High torque active mechanism for orthotic and/or prosthetic devices
A high torque active mechanism for an orthotic and/or prosthetic joint using a primary brake which can be provide by magnetorheological (MR) rotational damper incorporating and an additional friction brake mechanism driven by the braking force generated by the MR damper. This combination of MR damper and friction brake mechanism allows an increase in torque density while keeping the same level of motion control offered by the MR damper alone. The increased torque density achieved by this high torque active mechanism allows to minimize the size of the actuating system, i.e. its diameter and/or breath, while maximizing its braking torque capability. In this regard, the friction brake mechanism is advantageously positioned around the MR damper, such that the dimension of the package is minimized.
1. A torque sensor for an orthotic or prosthetic device comprising a joint portion thereof for providing flexion and extension movement of the device, an actuator providing a controllable force during at least one of the flexion and extension movements, and a frictional band member configured to generate a frictional force during flexion and/or extension movements, said torque sensor comprising:
a deformable portion mounted to the joint portion; and
a sensor in operational communication with said deformable portion to measure a deformation of said deformable portion,
wherein when a braking torque is provided by the actuator the frictional band member provides an additional braking torque which is transmitted to said deformable portion causing deformation thereof, and said sensor measures the deformation of said deformable portion thereby allowing for determining the torque.
2. A torque sensor according to claim 1 , wherein said deformable portion comprises a deformable strip and a deformable frame, the deformable strip mounted within the deformable frame.
3. A torque sensor for an orthotic or prosthetic device according to claim 1 , wherein the torque sensor comprises a strain-sensor.
4. A prosthetic or orthtotic device comprising:
at least one device portion;
a joint portion for providing for said at least one device portion to pivot between flexion and extension movements relative to another adjacent device portion or an adjacent limb segment of the user, the joint portion further comprising an actuator providing a controllable force during at least one of the flexion and extension movements;
a frictional band member configured to generate a frictional force on the joint portion during flexion and/or extension movements provided by the joint portion; and
a torque sensor comprising a deformable portion mounted to said joint portion, and a sensor portion in operational communication with said deformable portion to measure a deformation of said deformable portion,
wherein when a braking torque is provided by the actuator said frictional band member provides an additional braking torque which is transmitted to said deformable portion causing deformation thereof, and said sensor measures the deformation of said deformable portion thereby allowing for determining the torque.
5. A prosthetic or orthotic device according to claim 4 , further comprising at least one support for mounting the device portion to the joint portion.
6. A prosthetic or orthotic device according to claim 5 , wherein the torque sensor is positioned on the at least one support.
7. A prosthetic or orthotic device according to claim 5 , further comprising at least one support for mounting the another adjacent device portion or an adjacent limb segment of the user to the joint portion.
8. A prosthetic or orthotic device according to claim 4 , wherein said deformable portion comprises a deformable strip and a deformable frame, the deformable strip mounted within the deformable frame.
9. A prosthetic or orthotic device according to claim 4 , further comprising a pressure pad adjacent the frictional band member and configured to reversibly cause the frictional band member to be pushed onto the joint portion such that the frictional band member generates the frictional force when pushed by the pressure pad.
10. A prosthetic or orthotic device according to claim 9 , wherein the pressure pad comprises a lever.
11. A prosthetic or orthotic device according to claim 4 , wherein the joint portion comprises a drum, and the frictional band member is configured to generate the frictional force by contacting the drum.
12. A prosthetic or orthotic device according to claim 4 , wherein the joint portion further comprises an actuator configured to controllably exert a rotational force on the at least one device portion.
13. A prosthetic or orthotic device according to claim 12 , wherein the actuator comprises a MR damper.
14. A prosthetic or orthotic device according to claim 12 , wherein the actuator comprises a mechanical actuator.
15. A prosthetic or orthotic device according to claim 12 , wherein the actuator comprises an electric actuator.
16. A prosthetic or orthotic device according to claim 12 , wherein the actuator comprises a pneumatic actuator.
17. A prosthetic or orthotic device according to claim 12 , wherein the actuator comprises a hydraulic actuator.
18. A prosthetic or orthotic device according to claim 4 , wherein the torque sensor comprises a strain-sensor.
19. A prosthetic or orthotic device according to claim 4 , wherein the joint portion comprises a knee joint.