Research on non-singular terminal sliding mode control of a fuzzy switching term in UUV dynamic recovery

This paper transform the dynamic docking control problem into the state synchronization control problem between the UUV and the mother ship, and proposes a control method that non-singular terminal sliding mode control under the condition of dynamic docking of UUV. Through the analysis of lyapunov stability theory, it is proved that the control method can make the synchronous system converge to the planned sliding mode surface in a finite time, solve the problem of gradual convergence of the system under ordinary sliding mode control. Then, the traditional switching function in the controller is replaced with a hyperbolic tangent function, and a fuzzy control rate is proposed to adaptively control it. The simulation proves that this method can effectively reduce the chattering caused by the system itself, and has obvious effects in dealing with external interference issues such as ocean currents. Finally, the overall simulation of the controller was carried out, and experimental tests were carried out in the ocean. The results show that the controller can meet the time and accuracy requirements of UUV dynamic docking.