A Stable Control Framework for Continuous Robot-Assisted Training

In this paper, a control framework for an upper limb exoskeleton rehabilitation robot is proposed, emphasising the strict implementation of safety protocols to guarantee that patients in the early stages of rehabilitation can accurately follow normal human activity postures for training. First, the interpolating polynomials are optimised by considering the minimum-jerk principle in the generation of the reference trajectories required for training; Then a motion-dependent function is proposed for smooth switching between two modes, normal exercise and safe stop; Finally, a non-singular terminal sliding mode (NTSM) method is proposed for accurately tracking the required joint angles, and the exoskeleton tracking error tends to be zero within a finite period of time. Furthermore, the stability of the entire system is ensured by Lyapunov stability. The simulation outcomes illustrate the efficacy and resilience of the proposed control framework.