The Application And Research On The Roust Control In The Steering System

The heading control of the ship is very important motion control system of the ship. Except closely related to the sail conditions, the dynamic motion characteristics are subjected to disturbances such as ocean wind, ocean wave and ocean current. So the hydro-dynamic load and disturbance are complicated. These make much uncertainties occur in the heading control system. It is hardly to control the motion of the ship because the heading control is so complicated. In order to control effectively on the premise of economization and failsafe, the steering system and heading control system are designed in this paper taking example for one ship.- The compose and working principle of the steering system are analyzed. The displacement control system of the variable-displacement pump and the steering system are modeling. Then the transfer function model of hydraulic steering system is set up. Through the analysis of the heading control system, the mathematic model of ship motion, environmental disturbance and automatic pilot system are established respectively. On the basis of classical PID control theory, the PID controllers of steering system and heading control system are designed and simulated. It is showed that the precision of the PID controllers is low for the parametric uncertainties and disturbances. To improve the robustness and robust performances of steering system, the robust controller based on H_∞mixed sensitivity for the steering system is proposed through the analysis of uncertainties. And the robust controller for automatic pilot system is to improve the interference immunity. Compared with the PID controllers, the robust controller not only can stabilize when parameters are perturbed, but also improve the tracking accuracy of the steering system. It is testified that the steering system with robust controller can match well with the automatic pilot system as a close-loop system. It has stronger robustness and good performances of operation in the followup and heading control state.