Torque sensing and determination for a prosthetic joint actuation system

A prosthetic knee device comprising:

• a joint mechanism positioned between a shank structure and an adjacent prosthetic portion or a limb segment of a user, the joint mechanism comprising an actuator;
• a transmission assembly, wherein a torque applied to the joint mechanism is used to control a rotational movement of the joint mechanism, the transmission assembly comprising:
• an output component comprising:
• a base coupled to an actuator of the joint mechanism;
• a first arm and a second arm extending from the base and forming a closed loop at distal ends of the first and second arms;
• wherein the distal end of the second arm and the distal end of the first arm are coupled together at a distal connection point;
• a gap between the first arm and the second arm extending from the base to the distal connection point;
• a distal attachment portion comprising an opening and rotatably coupled to a shank portion of the prosthetic device;
• a fastener positioned in the opening of the distal attachment portion, the fastener configured to rotatably coupled the distal attachment portion to the shank portion of the prosthetic device;
• and
• a sensor configured to measure rotation of the distal attachment portion relative to the shank portion of the prosthetic device when a torque is applied to the base.