Trajectory tracking control of autonomous underwater vehicles based on a predefined time control strategy

Abstract This paper investigates the problem of trajectory tracking control of underactuated autonomous underwater vehicles (AUVs) with predefined time convergence. To this end, a predefined time nonlinear disturbance observer (PTNDO) is designed with the aim of accurately estimating unknown external disturbances. This observer is capable of capturing the dynamic influences on the AUV in real time to support the subsequent control strategy. By setting the time parameters reasonably, the convergence time of the system can be set in advance, thus ensuring that the desired tracking effect is achieved within a specific time. In addition, a predefined time backstepping controller (PTBC) is designed for the problem of AUV trajectory tracking. Theoretical analysis shows that the upper limit of its convergence time is only determined by a constant, which simplifies the parameter tuning process and enhances the practicability compared with the existing finite/fixed time control methods. The effectiveness and superiority of the proposed method are verified through further simulation studies, which show that the control strategy has good trajectory tracking performance.