Variable Exponent Adaptive Nonsingular Terminal Sliding Mode Control for Uncertain Second-Order Nonlinear Systems

For the trajectory tracking problem of second-order nonlinear uncertain systems, this paper proposes a new adaptive nonsingular terminal sliding-mode control method. A novel sliding variable with variable exponent is designed to improve convergence speed and tracking accuracy, and a saturation function is adopted to avoid singularity issues. Additionally, an adaptive mechanism is introduced to compensate for the parameter uncertainties and external unknown disturbances in the system, ensuring the system's robustness. Considering the physical limitations of the controller, simulation experiments are conducted on a typical 2-link robotic manipulator. The results validate the effectiveness and robustness of the proposed control method.