ABSTRACT
This chapter proposes an adaptive control scheme for underactuated ships with input saturation. 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. Globally asymptotically convergence of tracking errors has been established and a simulation example is given to illustrate the effectiveness of the proposed control scheme. Normally the tracking and stabilization control of underactuated ships are investigated separately due to the existence of underactuation, and the control schemes cannot be applied each other. In the tracking control, backstepping and the Lyapunov function approach are used extensively. In a controller that achieves practical tracking of arbitrary reference trajectories for underactuated ships using the transverse function approach. However, the stabilization control of underactuated ships is normally solved by exploring the chained structure of the dynamics of the ship through variable exchange.
