Characterization of a dual PID-ILC FES controller for FES-robot control of swing phase of walking

Abstract

Accurate control of neuroprosthesis (NP) to restore walking ability in spinal cord injured people is still challenging due to the non-linear characteristics of neuromuscular tissue. The presence of an external exoskeleton in hybrid configuration (hybrid exoskeleton) that provides joint support and monitoring capabilities, can be exploited for control of the NP. In this work we present the characterization experiments of a dual NP controller, comprised by a proportional-integral-derivative (PID) and an iterative learning algorithm of a hybrid exoskeleton. It is found that non-causal learning allows to overcome the electromechanical delay of knee flexor muscles. Besides, the PID controller decreases stimulation performance.