NN-backstepping for diving control of an underactuated AUV

This paper develops a path following controller for an AUV in vertical plane. With the given tracking error expressed in Serret-Frenet frame, a backstepping method based on feedback gain is adopted rather than directly nonlinear cancellation or feedback linearization. An adaptive neural network (NN) compensator is introduced due to the dynamics of AUV are highly nonlinear and the hydrodynamic coefficients are difficult to be accurately estimated at priori. The network weights adaptation law is derived from the Lyapunov stability analysis, and the resulting nonlinear feedback control scheme can guarantee that all the signals in the closed loop system are uniformly ultimately bounded (UUB). The simulation results demonstrate the effectiveness of proposed method with INFANTE AUV model.