Path following control of underactuated ships based on nonswitch analytic model predictive control

A path following controller is developed for underactuated ships with only surge force and yaw moment available to follow a predefined path. The proposed controller is based on nonswitch analytic model predictive control. It is shown that the optimal control law for a nonlinear path following system with ill-defined relative degree is continuous and nonsingular. The problem of ill-defined relative degree is solved. The path-following ability of the nonlinear system is guaranteed. Numerical simulations are provided to demonstrate the effectiveness of the proposed control law. © 2010 South China University of Technology and Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg.