Model-free adaptive iterative sliding mode control for a robotic exoskeleton trajectory tracking system

This paper is devoted to the tracking control problem for a robotic exoskeleton with the model-free adaptive iterative sliding mode control (MFAISMC) approach. Firstly, the dynamical model of exoskeleton is converted into a linear discrete model by compact form dynamic linearisation (CFDL) with iteration method. Then, based on the linear model, an MFAISMC algorithm is proposed to control the system tracking the desired time-varying trajectories, which just depends on the iterative input and output data of each joint of the exoskeleton. It is proved that the convergence of both tracking error and time-varying parameters can be guaranteed with the increasing iterative numbers. Finally, the effectiveness and superiority of the presented method are verified by related simulation results.