Adaptive–robust control of autonomous underwater vehicle with unknown system dynamics

Abstract

This chapter introduces a new class of ARC tracking control framework for AUV without any knowledge of the system dynamics parameters. Conventional ARC strategies either require complete/partial knowledge of the systems dynamics parameters or presume the overall uncertainty (or its time derivative) is upper bounded by a constant. However, such presumption is restrictive for systems like AUV which has explicit presence of states in its structure of system uncertainty.Besides, many of the existing AR-based designs suffer from the over-and underestimation problems of switching gains. In such regards, the proposed ASRC law not only avoids restrictive presumptions of system uncertainty being upper bounded by a constant, it simultaneously alleviates the over-and underestimation problems of switching gain. Futher, the effectiveness of the ASRC law is verified in simulation in comparison with the existing ASMC law under the scenario of uncertain system dynamics. An important future work would be to formulate an ARC for AUV considering input/output delay since data acquisition and localization in underwater scenario is always challenging and a controller needs to take care of such circumstances.