Global adaptive stabilization control of underactuated ships with input saturation

In this paper, global adaptive stabilization control of an underactuated ship in the presence of input saturation is investigated. By proposing a novel Nussbaum-type function, the augmented system approach is extended to the saturated and interconnected nonaffine nonlinear systems and Lyapunov stability is established. The uncertain parameters and external disturbances are not required to be in a known compact set. Globally asymptotically convergence of tracking errors has been established and a simulation example is given to illustrate the effectiveness of the proposed control scheme.