Output feedback control of an actuated lower limb orthosis with bounded input

Purpose – The purpose of this paper is the control of lower limb orthosis acting at the knee joint level for a passive rehabilitation purpose. Design/methodology/approach – A control law, based on a saturated proportional derivative controller, is proposed in order to drive the shank-foot-orthosis system along a desired trajectory. Findings – The proposed control law is tested in real time using the orthosis EICOSI of the LISSI-Laboratory. The experiments show that the proposed control law is capable of providing satisfactory trajectory tracking performance given only the knee joint angle measurement. Moreover, the control law is robust with respect to external disturbances. Originality/value – Robust control of an actuated lower limb orthosis.