Global tracking control of underactuated surface vessels with non-diagonal matrices

Abstract

In this paper, two control laws are proposed to solve the tracking control problem of underactuated surface vessels with non-diagonal inertia and damping matrices. Based on the inherent cascaded structure of dynamics, the original tacking control problem of vessels is converted to stabilization control problem of two subsystems. Then, two tracking control laws are designed respectively for known and unknown model parameters. The first surge control law is simple without any model parameter, and hence is possible to be extended to the case of unknown model parameters. Stability analysis indicates that both the two control laws realize global K-exponential tracking under persistently exciting condition. Effectiveness of the proposed controllers is demonstrated by numerical simulations.