Global Fast Terminal Sliding Mode Controller Design for Low Speed Servo System with Friction

Based on the model of servo system with nonlinear friction disturbance, a global fast terminal sliding mode controller (TSMC) is developed in this paper. With the introduction of the nonlinear function in the design of the sliding hyperplane, it is guaranteed that the system tracking error converges to zero in finite time. In addition, the control law doesn\´t include switching item, it is continuous, so the chattering can be eliminated. Simulated results show that the proposed controller not only can eliminate the "crawling" and "flat top" phenomena effectively, but also decrease the output chattering significantly, provides high-performance dynamic characteristics, and is robust with regard to the friction disturbance.