Amputation below the knee is an increasingly common disability that reduces mobility and adversely affects quality of life. In order to help those people, the team at HuMoTech created an robotic ankle-foot prosthesis that can accurately reproduce a large variety of prosthetic ankle behaviors, including increased push-off.

The prosthesis provides controllable torque about the ankle axis. The keel portion of the device is controlled by an external actuator unit, while a passive heel spring provides compliance in the early stance phase of the walking cycle.

The control signals for the high-performance torque control are determined using the actual torque applied at the ankle prosthesis together with the prosthesis joint angle. The Speedgoat Performance real-time target machine measures such, torque and angle, using real-time measurements from a load cell and an encoder, respectively, and computes motor commands to regulate ankle joint impedance. Further information will be shown in the video.