Dynamical sliding mode control for the trajectory tracking of underactuated unmanned underwater vehicles

This paper proposes a novel adaptive dynamical sliding mode control based methodology to design control algorithms for the trajectory tracking of underactuated unmanned underwater vehicles (UUVs). The main advantage of the approach is that the combination of backstepping and sliding mode control enhances the robustness of an UUV in the presence of systematical uncertainty and environmental disturbances. The position and attitude dynamical equations of an underactuated UUV are first represented and analyzed using coordinate transformation with the aid of backstepping technique. Subsequently, the output feedback problem is tackled by employing adaptive sliding mode control to estimate the systematical uncertain states required by the stable velocity tracking controller. The final controlled system can be proved to be globally asymptotically stable based on Lyapunov stability theory. Simulations performed on an underactuated UUV demonstrate the effectiveness of the proposed method.