Trajectory Tracking Control of UUV Based on Backstepping Sliding Mode With Fuzzy Switching Gain in Diving Plane

Considering the actual situation of time-varying interference in the underwater environment, a trajectory tracking control method for an underactuated Unmanned Underwater Vehicle (UUV) underwater exploration based on backstepping sliding mode with fuzzy switching gain is designed in this paper. Firstly, the motion equations of UUV in diving plane are given. Secondly, the virtual control variable is designed to replace the pitch angle to avoid the singular value phenomenon. Combining with the backstepping technique, the fuzzy switching sliding mode controller is proposed. Thirdly, in order to decrease the chattering phenomenon of sliding mode control, the fuzzy rule of sliding mode gain is designed. Fourthly, based on Lyapunov theory and comparison principle, the global asymptotic stability of UUV closed-loop tracking error system is proved. Finally, the simulation results demonstrate the effectiveness and robustness of the proposed controller.