Lower limb prosthesis

1. A lower limb prosthesis, comprising:

a foot member; and

a main body rotatably coupled to the foot member at a joint comprising a joint axis, wherein the main body comprises a housing, an actuator, and a transmission comprising at least one intermediate stage and a final stage, and wherein the actuator is configured to transmit an actuator torque to the transmission, the at least one intermediate stage is configured to transmit an intermediate torque about an intermediate axis, and the final stage is configured to transmit a final torque about the joint axis to the foot member, wherein the at least one intermediate stage comprises a first intermediate stage and a second intermediate stage engaged with the first intermediate stage, wherein the first intermediate stage is configured to transmit a first intermediate torque about a first intermediate axis and the second intermediate stage is configured to transmit a second intermediate torque about a second intermediate axis, wherein the first intermediate stage is an epicyclic stage and the second intermediate stage comprises a belt and a pulley, or a chain and a sprocket.

2. The lower limb prosthesis of claim 1 , wherein the main body is rotatably coupled to the foot member through a foot coupler, and wherein the final torque is transmitted to the foot member via the foot coupler.

3. The lower limb prosthesis of claim 1 , wherein a direction vector of the first intermediate axis and a direction vector of the second intermediate axis are parallel to a direction vector of the joint axis.

4. The lower limb prosthesis of claim 1 , wherein a direction vector of the first intermediate axis and a direction vector of the second intermediate axis are perpendicular to a direction vector of the joint axis.

5. The lower limb prosthesis of claim 1 , wherein the final stage comprises a hypoid gear.

6. The lower limb prosthesis of claim 1 , further comprising a controller and a sensor, wherein the controller receives prosthetic information from the sensor, and wherein the controller is configured to use at least the prosthetic information to control the actuator.

7. The lower limb prosthesis of claim 6 , wherein the sensor comprises an absolute encoder, and the prosthetic information comprises a position signal indicating an angular position of the foot member relative to the main body.

8. The lower limb prosthesis of claim 7 , wherein at least a portion of the absolute encoder is positioned on the final stage of the transmission.

9. The lower limb prosthesis of claim 6 , wherein the sensor comprises an incremental encoder, and the prosthetic information comprises an incremental signal indicating a change in an angular position.

10. The lower limb prosthesis of claim 9 , wherein the incremental encoder is located on the actuator, and the angular position is an angular position of a rotor of the actuator.

11. The lower limb prosthesis of claim 9 , wherein the incremental encoder is located on an intermediate stage of the at least one intermediate stage, and the angular position is an angular position of a shaft of the intermediate stage.

12. The lower limb prosthesis of claim 6 , wherein the sensor comprises a torque sensor, and the prosthetic information comprises a torque signal indicating the final torque, and wherein at least a portion of the torque sensor is located on a foot coupler fixedly attached to the foot member, and wherein the final torque is transmitted to the foot member via the foot coupler.

13. A lower limb prosthesis, comprising:

a foot member; and

a main body rotatably coupled to the foot member at a joint comprising a joint axis, wherein the main body comprises a housing, an actuator, and a transmission comprising at least one intermediate stage and a final stage, and wherein the actuator is configured to transmit an actuator torque to the transmission, the at least one intermediate stage is configured to transmit an intermediate torque about an intermediate axis, and the final stage is configured to transmit a final torque about the joint axis to the foot member, wherein the at least one intermediate stage comprises a first intermediate stage and a second intermediate stage engaged with the first intermediate stage, wherein the first intermediate stage is configured to transmit a first intermediate torque about the intermediate axis and the second intermediate stage is configured to transmit a second intermediate torque about the same intermediate axis, wherein the first intermediate stage is a first epicyclic stage and the second intermediate stage is a second epicyclic stage.

14. The lower limb prosthesis of claim 13 , wherein the first epicyclic stage has a planetary configuration and the second epicyclic stage has a star configuration.