Output feedback Control of an Actuated Lower Limb Orthosis with Bounded Input

International audienceThe paper deals with the control of a lower limb orthosis acting at the knee joint level for a passive rehabilitation purpose. A bounded control torque computed over an output feedback is applied to ensure the shank-foot-orthosis stability while tracking a desired trajectory. The feedback is based on the knee joint angle and an estimate of its angular velocity. The stability of the shank-foot-orthosis system is proved by means of Lyapunov theory. The proposed control law is robust with respect to external disturbances and satisfies the power limitation constraints. The efficiency of the proposed control law is shown through experimental tests using the orthosis EICOSI of the LISSI Lab