Non-singular Fast Terminal Sliding Mode Tracking Control of a 2-DOF Robotic Manipulator Using Finite-Time Extended State Observer

This paper studies the position tracking control of rigid robotic manipulators under the circumstance of parameter uncertainties and external time-varying disturbances. For the 2-DOF rigid manipulator, a non-singular fast terminal sliding mode control (NFTSMC) scheme is employed based on a finite-time extended state observer (FTESO) to improve both the dynamic response and the disturbance rejection performance. The NFTSMC method is employed to evade the singularity of conventional terminal sliding mode control method and speed up the state reaching the sliding surface. The FTESO can observe the lumped disturbances in finite time and perform forward compensation to attenuate the chattering phenomenon of sliding mode control. The closed-loop system stability is demonstrated rigorously based on the Lyapunov theory. Comparative simulation results are given to prove the superiority of the proposed method.