Tracking Control of an Autonomous Underwater Vehicle: Higher-Order Sliding Mode Control Approach

Tracking control of autonomous underwater vehicle (AUV) is complicated due to highly nonlinear dynamics, structural and non-structural uncertainties, and inevitable external disturbances. In this study, the control algorithm for tracking operation of AUV in 3D workspace is proposed. This algorithm is based on terminal sliding mode control technique, which leads to fast response, time-limited convergence and robustness against uncertainties and external disturbances. To this end, first the trajectory planning and convergence of position tracking errors is introduced using kinematics model. Next, control laws are developed and the stability of the proposed control lows are analyzed. Finally, the system performance using various control laws of terminal sliding mode tracking control (TSMTC), fast terminal sliding mode tracking control (FTSMTC) and feedback linearizing tracking control (FLTC) are compared. Obtained results show efficiency of the proposed FTSMTC algorithm in accelerating route tracking and reasonable performance in handling disturbances in terms of tracking errors.