Robust control design of arm exoskeleton based on sliding mode control

This paper describes the design of nonlinear control based sliding mode control for the upper-limb rehabilitation exoskeleton. The proposed controller has robustness against uncertainties of dynamic parameters. The control law provides robustness against disturbances with unknown bounds. To investigate the performance of the proposed control method, simulations are conducted for a nonlinear upper-limb exoskeleton comparing with a computed torque control method. STM32F4Discovery was implemented as the main controller either a traditional controller or a sliding mode control. In the experiment, trajectory tracking in joint space were conducted to evaluate the performance of the developed robot and the controller. Experimental results show that the robot can effectively track the desired S-curve trajectories corresponding to passive arm movement.