Tracking Control of an Articulated Intervention Autonomous Underwater Vehicle in 6DOF Using Generalized Super-twisting: Theory and Experiments

The articulated intervention autonomous underwater vehicle (AIAUV) is an underwater swimming manipulator with intervention capabilities. Station-keeping and trajectory tracking are essential for the AIAUV to be able to move in confined spaces and to perform intervention tasks. In this article, we propose using a generalized super-twisting algorithm (GSTA), which is an extension of the regular super-twisting algorithm, for the trajectory tracking of the position and orientation of the base of the AIAUV in six degrees of freedom (6DOF). We also propose using a higher-order sliding mode observer (HOSMO) for estimating the linear and angular velocities when velocity measurements are unavailable. Furthermore, we show the ultimate boundedness of the tracking errors for a control law using the GSTA and for a control law that combines the GSTA with an HOSMO. We also prove that the GSTA gives global uniform finite-time stability. Finally, we demonstrate the applicability of the proposed control laws with comprehensive simulation and experimental results.