Control System Design for Dynamic Positioning Ships Using Nonlinear Passive Observer Backstepping

Aiming at the characteristics of nonlinear system of dynamic positioning system by considering the influence of environmental disturbance, a global exponential stability (GES) nonlinear output feedback control algorithm was proposed in this paper. The system includes a nonlinear passive observer used to filter out the high frequency (HF) disturbance of measured position and heading, as well as to estimate the velocity of the ship. Observed position and heading signal were used to design the backstepping controller with integral action, which can improve the dynamic response speed of the closed-loop control system. The global exponential stability of the total system is proved by the Lyapunov stability theory. The performance of the designed controller has been verified in computer simulation.