Trajectory Tracking Control of Hydraulic Rehabilitation Exoskeleton Leg with Output Constraint

This paper addresses the trajectory tracking control of lower limb rehabilitation exoskeleton leg driven by hydraulic actuator with output constraint. A barrier Lyapunov function is utilized to handle the output constraint of the hydraulic actuator. The radial basis functions neural networks are used to approximate the disturbance and unmodeled uncertainties. Under the effect of the designed control scheme, the output constraint problem is well averted, and the involved signals of the rehabilitation exoskeleton are semi globally bounded. The tracking convergence of the closed-loop system is demonstrated by using mathematical method. The performance of the designed controller is illustrated by numerical simulations.