Development and Evaluation of a Powered Artificial Gastrocnemius for Transtibial Amputee Gait

Figure 5

Torque control schematic. The control system for the AG is composed of an inner torque-controller loop that enforces desired torque at the joint and an outer loop involving a neuromuscular model as a controller that receives joint kinematics as input. The controller switches between open-loop control (stance) and closed-loop torque control (swing) as appropriate given the gait cycle phase. Motor torque control is performed at the lowest level by controlling motor current, scaled by the torque constant, .