DOPH∞-based path-following control for underactuated marine vehicles with multiple disturbances and constraints

Abstract

This paper presents a new robust path-following (PF) control method for underactuated marine vehicles with multiple disturbances and constraints. To improve the control performance and reduce the conservativeness of many PF control strategies described in the previous literature, which treated the multiple disturbances of the underactuated marine vehicle as a single equivalent disturbance, the multiple disturbances are categorized into two types according to their characteristics in this paper, i.e., the slowly varying disturbance and the H2-norm bounded disturbance. Then, a composite controller combining Disturbance-Observer-based control with H∞ control, which can be abbreviated as DOPH∞-based controller, is constructed for the control model. A disturbance observer is designed for estimating and eliminating the slowly varying disturbance, and the H∞ theory is used to attenuate the H2-norm bounded disturbance. Moreover, to improve the practicability of the control method in engineering applications, the virtual yaw angular velocity constraint and the actuator constraints are considered, and the auxiliary dynamic compensators are used to compensate for them. Finally, the closed-loop stability of the whole system is guaranteed. Simulations and comparative analyses are presented to demonstrate the effectiveness and robustness of the presented strategy.