Nonlinear tracking differentiator with inverse-hyperbolic-sine-function for tracking control of multi-degree-of-freedom manipulators

This paper introduces a novel nonlinear tracking differentiator (TD) for multi-degree-of-freedom manipulator tracking control systems with unknown states. The proposed TD utilizes the inverse hyperbolic sine function (IHSTD), which combines linearity and nonlinearity, to enhance the rapidity and stability of the tracking performance in manipulator systems. Additionally, a terminal attractor function is incorporated into the IHSTD to effectively reduce chattering in control tracking systems. Simulation results are presented, demonstrating the superior performance of the proposed IHSTD compared to other TDs in terms of faster signal tracking and more effective noise suppression. Furthermore, the IHSTD is employed to estimate the unknown states in the sliding mode control (SMC) based on the radial basis function (RBF), which serves as the tracking controller for the manipulator system. Simulation results validate the effectiveness of the proposed control method, highlighting their excellent tracking performance and robustness to disturbances in complex environments.