Robust Finite Time Tracking Control for the Knee Joint Exoskeleton Robot

In this paper, finite time tracking problem for the knee joint exoskeleton (orthosis) robot is addressed in the presence of model uncertainties and external disturbances. Based on the second order non-singular terminal sliding mode control (NTSMC) method, a novel actuator’s torque (control input) is designed to exactly reach the subject’s shank to the desired trajectory within the adjustable total finite time. The global finite time stability of the closed-loop exoskeleton robot system is mathematically proven by using Lyapunov theorem. Moreover, a new relation is derived for determining the required finite time. Finally, a numerical simulation is given to illustrate the good performance of the suggested actuator’s torque. .