Cartesian sliding mode tracking control of an exoskeleton robot based on time delay estimation

This paper presents a Cartesian adaptive control based on a robust Sliding Mode and Time Delay Estimation (CSMTDE) for controlling a redundant exoskeleton robot called ETS-MARSE subject to uncertain nonlinear dynamics and external forces. The robustness and accuracy are achieved by selecting a sliding Cartesian surface and a sliding joint surface. The combination between them is done by the nonlinear Jacobian matrix. The stability of the closed loop system is solved systematically, ensuring asymptotic convergence of the output tracking errors. Simulation results manifest the efficiency of the suggested control to provide an excellent performance despite the presence of dynamic uncertainties and external disturbances.