Stability study and robustness analysis of an exoskeleton-upper limb system

This paper deals with a stability study and a robustness analysis of an exoskeleton- upper limb system, used for rehabilitation. The considered system is a robot with two degrees of freedom controlled by a Model Free Terminal Sliding Mode algorithm. The objective is to control the flexion/extension movement of the shoulder and the elbow in presence of uncertainties and disturbances. The dynamic model of the system was presented. An Input-to-State Stability study is realized to demonstrate the stability of the system. A robustness analysis using Monte Carlo method is developed. Simulation results are provided to prove the performances and the effectiveness of the Model Free Terminal Sliding mode algorithm and the stability of the system face to disturbances and uncertainties.