This paper aims to study the problem of nonlinear six-degrees-of-freedom (DOFs) autonomous underwater vehicle (AUV) trajectory tracking.

To this end, the line-of-sight (LOS) guidance law of three-dimensional trajectory with variable forward-looking distance is designed, and the stability of the guidance law is proved by Lyapunov stability criterion, and the adaptive S-plane control is used to control the heading, trim angle and longitudianal velocity of AUV. Moreover, taking the REMUS 100 AUV as an example, Matlab-based simulation on the control of the heading, trim angle and longitudinal velocity and the space straight line and curve trajectory tracking are carried out to verify the validity of the proposed LOS guidance law.

The results show that, for the nonlinear AUV control, compared with the traditional S-plane control, the adaptive S-plane control can reduce the difficulty of tuning control parameters and has stronger anti-jamming ability. Compared with the traditional LOS guidance law, the designed LOS guidance law can make AUV track the reference trajectory faster.

The designed trajectory tracking control algorithm can realize the three-dimensional trajectory tracking for AUV, and be used to improve the vehicle's maneuverability.