Robust-save energy controller on an autonomous underwater vehicle with obstacles avoidance

Abstract

This paper presents a robust-saved energy control and obstacles avoidance technique for an Autonomous Underwater Vehicle (AUV). A super twisting sliding mode which consists of discontinues and continuous function is engaged as a robust control. A discontinuous function is useful to switch between two different systems; thus, the disturbance's effect can be minimized. However, it is resulting a high-infinite frequency which degrades the robustness of an AUV, hence, a continuous function is useful to smoothness the switching movement. Instead of line trajectory, a region shape based on region-tracking control is included to save the energy usage, whilst, the calculation of repulsive force between an AUV and obstacles is used to avoid the collision. To observe the performance, some simulations on a 6-DOF-AUV are presented. During the obstacles avoidance, it is shown that the proposed control allows the AUV to produce 0.6 (m) less error without oscillation, obtain 80 (s) faster time of error convergence and save 9.3 % of energy consumption compared to modified Function-based Augmented Proposal Derivative (PFAPD). Overall, the proposed method contributes to a robust, energy saving and obstacles avoidances control for an AUV under disturbance’s effect.