Disturbance observer-based robust prescribed-time sliding mode tracking control for robotic manipulator systems:...

This paper presents a robust prescribed-time sliding mode control (RPTSMC) method based on prescribed-time disturbance observer (PTDO) for the trajectory tracking problem of robotic manipulators. At first, a novel PTDO is designed for the estimation of lumped uncertainty, comprising parameter perturbations, joint friction, and external disturbances. It is easy to implement as no prior knowledge of uncertainty is required and it ensures that the lumped uncertainty can be compensated for within a prescribed-time frame. Subsequently, a novel RPTSMC strategy is developed building upon the well-designed PTDO, which enables the robotic manipulator to achieve prescribed-time trajectory tracking. Furthermore, a rigorous stability analysis results for both the PTDO and the RPTSMC are provided based on the Lyapunov method. Finally, comparative experiments on the Unitree Z1 robotic manipulator platform verify the effectiveness and advancement of the developed control scheme.