Non-singular terminal super-twitsing control of servo systems with backlash

To improve the control performance of servo systems under time-varying disturbances, a nonsingular terminal super twisting sliding mode control (NTSTC) method based on a reduced-order generalized proportional-integral observer is proposed. The method combines the third-order super-twisting and non-singular fast sliding mode to form an improved non-singular terminal super-twisting controller, while the reduced-order generalized proportional-integral observer is designed to accurately estimate the unknown part of the perturbation in real time and feed-forward compensation for NTSTC. The anti-interference ability and robustness of the motor control system are effectively improved, and the fault-tolerant control of the servo system under parameter disturbance and unknown disturbance is realized. Finally, the effectiveness of the proposed control algorithm is verified by simulation.