The optimal control based on vector guidance for dynamic positioning vessel rotating around a fixed point

The control for position and orientation in dynamically positioned vessel´s rotational movements around a fixed point is considered in this paper, a control method based on the optimal control theory and a vector guidance strategy is proposed. The nonlinear mathematical model of dynamically positioned vessel is built, and linearized by introducing the vessel parallel coordinate system. Through the proposed guidance strategy, the desired position vector is calculated according to the position vectors of rotation center in body-fixed frame and mass center in earth-fixed frame. By adding the integral term, taking the position deviation, orientation deviation and order forces as the quadratic performance index, a vector guided control method is proposed to ensure the stability of the system. The validity and the control effect of the proposed controller are verified by simulations.