Modelling and Control of Single Arm Exoskeleton for Upper Limb Rehabilitation Application using Hybrid Hierarchical Sliding Mode and PID Controllers

Assistive and rehabilitative robotics technologies have seen increasing adoptions in the industry and medical applications alike. This paper presents the dynamic modelling and control scheme of a single arm robotic exoskeleton that is aimed for rehabilitation and physiotherapy of upper limbs. The dynamic model was developed using Euler-Lagrange formulation and the obtained equations allow close analysis on different sources of dynamic torques, which exhibit highly non-linear behaviour. A hybrid hierarchical control scheme employing sliding mode (SMC) and PID controllers are proposed. Simulation were setup using Simulink to evaluate the ability of the proposed control scheme. The simulation results are presented and they show that the proposed control scheme was able to control and track the desired trajectory for multiple degrees-of-freedom.