Three-Dimensional Path Tracking Control of the Underactuated AUV Based on Backstepping Sliding Mode

Based on the improved backstepping method and sliding mode control principle, this paper studies the path tracking control problem of underactuated AUV considering the environmental position interference. The Serret-Frenet curve coordinate system is introduced, and the approach angle is designed, which decreases the path-following steady-state error. The integration of tracking error is used in the controller design to increase the robustness of the controller. In order to reduce the shaking, avoid differential explosion and optimize the tracking effect, a filter-based backstepping sliding mode controller is designed. A low-pass filter is used to approximate the virtual control signal to reduce chattering, and a second-order filter is used to avoid differential explosion. Finally, the numerical simulation results are shown to verify the control effect of the filtered backstepping sliding mode controller. Compared with the traditional backstepping sliding mode controller effect, the chattering of the controller output is significantly reduced. The AUV path tracking curve converges faster, the time taken to achieve stable tracking state is shorter, and the stability is improved.