Robust controller with a fixed compensator for underwater vehicle-manipulator systems including thruster dynamics

Abstract

This paper deals with a control scheme for underwater vehicle-manipulator systems with the dynamics of thrusters in the presence of uncertainties in its system parameters and bounded disturbances. The authors have developed a robust controller that overcomes thruster nonlinearities, which cause an uncontrollable system. However, the controller has disadvantages in its performances (e.g., steady-state errors). In this paper we develop a robust controller with a fixed compensator including an integral action. The objective of the compensator is to improve the performances of the controller. The ultimate boundedness of a tracking error is theoretically ensured in the control system. Furthermore, simulation results support the theoretical one.