Robust fixed-time tracking control for underactuated AUVs based on fixed-time disturbance observer

• Published in: Ocean engineering Vol. 266; p. 112567
• Main Authors: An, Shun, Wang, Longjin, He, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2022
• Subjects: Autonomous underwater vehicles; Backstepping control; Disturbance observer; Fixed-time control; Trajectory tracking; Backstepping control; Autonomous underwater vehicles; Disturbance observer; Fixed-time control; Trajectory tracking
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2022.112567

This paper investigates the fixed-time trajectory tracking control problem of underactuated autonomous underwater vehicles (AUVs) subject to external disturbances. The backstepping control technique and fixed-time control method are integrated to guarantee that the trajectory of the AUV converges to the reference trajectory within a fixed-time. A continuous fixed-time disturbance observer is developed to estimate the unknown external disturbances. A nonlinear first-order filter is applied to avoid the adverse effect of “explosion of complexity” inherent in the conventional backstepping. Theoretical analyses demonstrate that under the fixed-time backstepping controller, the tracking errors of the AUV will converge towards a residual set in fixed time. Simulation results illustrate the effectiveness and superiority of the proposed control method. •A robust fixed-time backstepping controller is proposed for underactuated autonomous underwater vehicles.•A continuous fixed-time disturbance observer is developed to handle the external disturbances.•A nonlinear first-order filter is introduced to solve the problem of “explosion of complexity”.