Global Terminal Sliding Mode Control With the Quick Reaching Law and Its Application

In order to overcome the disadvantages of the conventional sliding mode reaching law, such as the large chattering and the slow convergence rate, an improved quick reaching law is proposed. The reaching law is composed of two terms which can, respectively, play the leading role when the system is far away from or near to the sliding mode surface. Thus, the system can arrive at the sliding mode surface with the faster convergence rate from beginning to end. Some other advantages of the reaching law, such as converging to the sliding mode surface in a finite time, and the second-order sliding mode characteristic are proved. Furthermore, in order to speed up the convergence rate to the equilibrium point along the sliding mode surface, the global terminal sliding mode control based on the quick reaching law is designed. It is used to control the unmanned surface vehicle. Simulation results show that the control method has better control performance than the conventional methods.