A simulation study of an FES based rehabilitation control system

This paper studies the use of functional electrical stimulation (FES) method with movement in patients with paraplegia (SCI) for rehabilitation. When FES is applied to the muscles in patients with certain frequency and amplitude of electrical stimulation, the stimulated muscles generate contraction strength. The use of FES can effectively prevent muscle atrophy in patients with paraplegia, and produce good rehabilitation results. This paper is focused on the use of multi-channel FES to lower extremity and the control of multi-muscle to generate rehabilitation movements. Because of the complexity of human motion, this paper has established a three-dimensional musculoskeletal model of the human body. Based on this model, the control of multi-channel FES to achieve cycling has been simulated. The controller designed in this paper is divided into two layers: the outer layer is based on fuzzy control method and it generates desired torque which is needed for cycling movement; the inner layer is a composite controller based on feedforward and PID control, and this layer control of multi-channel FES stimulate muscles to produce desired torque for tracking purposes. The controller of the inner layer uses tracking differentiator to obtain derivative information for the control system. Finally, the simulation results provided shows the effectiveness of the proposed method.