Fractional-order super-twisting nonsingular terminal sliding mode control of 2-DOF robotics manipulators

In this study, a super-twisting algorithm, using the sliding surface as a fractional-order non-singular terminal sliding mode (NTSM), is presented. In robust control, one of the important problem is the reduction of system error and reduce the chattering. One of the most common applications of sliding mode controllers is about the reduction of chattering. Also, utilizing the fractional calculus in controller design brings more accuracy and reduces system errors. Utilizing a higher-order sliding mode controller using the super-twisting algorithm and the fractional-order non-single terminal sliding mode for the two-link serial robot is the novelty of the presented research. The design of the suggested controller is such that it is independent of the robotic manipulators model and is based on the system errors. Stability analysis of the close-loop system has performed using Lyapunov's method. The simulation results show high accuracy, fast convergence, and high robustness of the proposed fractional-order super-twisting nonsingular terminal sliding mode control.