Adaptive path following controller of underactuated ships using serret-frenet frame

This paper presents an adaptive path following control law to steer underactuated ships along a predefined path at a constant forward speed with uncertain parameters due to changes of added mass matrices. The proposed controller is based on analytic model predictive control and model reference adaptive control. The Serret-Frenet frame is used to describe the ship dynamics. The analytic model predictive control provides a systematic method rather than try-and-error method to get appropriate control parameters to guarantee the stability of the closed-loop system, and the well-defined relative degree is guaranteed by introducing output-redefinition. An identification algorithm based on model reference adaptive control is used to identify the uncertain parameters. Numerical simulations are provided to demonstrate the validity of the proposed control law.