Adaptive Sliding Mode Control for Multi-Segment Cable-Driven Continuum Manipulators

For a novel class of multi-segment cable-driven continuum manipulators incorporating elastic rods, the Euler-Lagrange modeling approach is initially employed to formulate the dynamic model of the multi-segment cable-driven continuum space manipulator. Subsequently, addressing the presence of external time-varying disturbances with unknown characteristics, an attitude control strategy based on adaptive sliding mode control is proposed. An adaptive control law is designed to mitigate the effects of unknown bounded disturbances from the environment. Leveraging this adaptive control law, an adaptive sliding mode controller is developed, capable of real-time estimation of the parameters of the unknown disturbances while harnessing the robustness of sliding mode control to address the limitations of conventional control strategies in managing time-varying disturbances. Through stability analysis of the closed-loop system conducted using Lyapunov theory, the asymptotic stability of the system and its superior disturbance rejection capabilities are confirmed. Simulation results demonstrate that, in comparison to the proportional-derivative (PD) controller, the adaptive sliding mode controller proposed in this study is effective in scenarios where the upper bound of disturbances is unknown, exhibiting enhanced tracking performance and reduced steady-state errors in attitude angles.