FES knee bending and stretching system with RISE-based tracking control for human limb

This paper considers a functional electrical stimulation (FES) knee bending and stretching system on robust integral of the sign of the error (RISE)-based tracking control for human limb. The knee bending and stretching motion on rowing exercises is modeled as an Euler Lagrange system by using a closed-chain mechanism. Considering the scleronomic holonomic constraint, the equation of motion expressed in terms of the seat position is obtained. The human thigh model can be divided into three pairs of antagonistic muscles. The torque of the thigh consists of a combination of torque produced by the Quadriceps and Hamstrings muscle groups. The Quadriceps and Hamstrings are contracted by the electrical stimulation, and the control of stimulation is designed applying a RISE-based control framework. Experiment results are shown on seven healthy individuals by using a rowing exercise machine. The results confirm that the proposed muscle stimulation method can realize the knee bending and stretching motion similar to voluntary tracking.