Compensation of error at the beginning of stimulation cycle via stimulation shifting in FES-assisted Exercise

This paper presents the cadence error compensation at the beginning of a stimulation cycle via stimulation shifting for functional electrical stimulation (FES)-assisted elliptical stepping exercise. Two control strategies are proposed to enhance the control with a fuzzy logic controller (FLC). The first method is a combination of FLC-controlled stimulation pulse width and fixed stimulation pulse width and the second method is a combination of cadence error and fixed error. The parameters of both methods are optimized using the particle swarm optimization (PSO) technique to obtain optimal parameter value. Based on the optimization and test result, both methods have shown promising performance and are able to reduce the cadence error and enhance the smoothness of exercise.