Abstract:

The existing nonsingular terminal sliding mode control (NTSMC) and nonsingular fast terminal sliding mode control share the same drawbacks of slow convergence speed and the convergence stagnation, and aiming at these problems, an improved method is proposed. Without losing nonsingularity, the index of the exponential terms of sliding surface is expanded from fraction to real, which increases the convergence speed and flexibility at the same time. By applying the fast terminal approaching law, the approaching movement is changed from linear or exponential movement to fast terminal movement. The reason for the occurrence of convergence stagnation is analyzed in detail, and a law that the design parameters should satisfy is deduced theoretically. Finally, course tracking simulations conducted on an unmanned platform validate the effectiveness of the improved method.