Underactuated AUV Three-Dimensional Path Tracking Control Based on Interference Observer and 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 error. 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. An interference observer is added to the tracking controller to improve the robustness and anti-interference ability of the controller. Finally, the numerical simulation results are shown to verify the control effect of the filtered backstepping sliding mode controller combined with the interference observer. The controller with interference observer has smaller static error and stronger anti-interference ability, which improves the robustness and stability.