Super-Twisting Extended State Observer-Based Recursive Terminal Sliding Mode Control for Robotic Systems

In this brief, a finite-time recursive terminal sliding mode control method for nonlinear robot systems based on super-twisting extended state observer (STESO) is proposed. Firstly, a new finite-time super-twisting extended state observer is proposed, which has the characteristics of simple parameter tuning and no need to calculate complicated inertia matrix inversion. Secondly, a novel error transformation approach predicated on a non-smooth funnel surface is devised. This method exhibits enhanced dynamic and steady-state performances in comparison to traditional error transformation techniques. Subsequently, it is incorporated into a recursive sliding mode controller design. By incorporating STESO into the controller, a compound sliding mode control strategy is proposed, which enables the robot system to achieve rapid and high-precision trajectory tracking. Finally, the effectiveness of the proposed control strategy is verified by the simulation results.