System and method for motion-controlled foot unit

A method for controlling a prosthetic ankle device, the method comprising:

• measuring, with at least one sensor, at least one of position and movement of a prosthetic ankle device, wherein the prosthetic ankle device comprises a foot unit, a single lower limb member pivotally attached to the foot unit and at least one actuator having a first end connected to the foot unit and a second end connected to the lower limb member, the at least one actuator configured to adjust an angle between the foot unit and the lower limb member;
• generating data indicative of the at least one of position and movement of the prosthetic ankle device;
• processing the data with a processing module to determine a gait cycle phase;
• and
• adjusting the prosthetic ankle device based on the determined gait cycle phase, wherein said adjusting comprises actuating the at least one actuator to move the foot unit relative to the lower limb member in a manner that substantially mimics movement of a healthy ankle, and wherein said adjusting further comprises, during a swing phase, first decreasing an ankle angle of the device to a dorsiflexion position and then increasing the ankle angle of the device to a plantarflexion position before contacting a ground surface.