A Study On The Integrated Control Of Ship Motion And Main Propulsion Using Linear Parameter-varying

The integrated control of ship motion and main engine propulsion based on linear parameter-varying (LPV) is systemically studied in this dissertation.Ship maneuverability processes the complicated and changeful characteristics. The varieties of ship speed and draft directly affect ship maneuverability. Therefore, these issues should be taken into account enough in the control research on ship steering and linear track-keeping. In addition, the main engine speed affects the ship motion state and maneuverability, and the ship motion state is correlationally close with the main engine speed and operation, so the ship motion and the main engine speed control are strongly coupled. Therefore the study of the integrated control of ship motion and main engine propulsion put forward would be significant for both theory and engineering.In order to simulate ship motion control, the model of B&W 10L90MC high power diesel and the MMG ship model of 5446 TEU large container ship are established. The disturbances of wind, wave, and flow are considered in the ship model. The models are verified via turning simulation compared with the data from the trial voyage condition.The LPV control theory is the extension of the theory with LMI in the LPV system. In this dissertation, the linear fractional transformation (LFT) and the polytopic of LPV control methods are introduced. According to schedule parameters measured or computed on-line, the LPV control theories such as pole placement, model switch, etc. are recommended, whose main characteristics lie in that the system gain is adjusted Therefore, the LPV control method can improve the system stability, dynamic characteristics and robust performance, which has been successfully used on the nonlinear fields control such as missile, robot, etc.Based on the analysis of dynamic properties of ship motion and main diesel engine, we introduce the LPV polytopic nonlinear control method to the control fields of ship motion and main diesel engine. In this dissertation, the control algorithms of LPV polytopic for ship steering, linear track-keeping and ship steering in shallow water are studied, and the integrated controls of ship motion and main engine propulsion are also studied.With ship speed and draft as the schedule parameters, the ship course model is translated into a LPV system. With main engine speed and advance coefficient of propeller as the scheduling parameters, the main engine speed control equation of the MMG model was translated into a LPV system. With ship speed as the schedule parameter, the command guidance of underactuated ship interacted track-keeping is translated into a LPV system. With ship speed and the maneuverability coefficients as the schedule parameter, the ship course model in shallow water is also translated into a LPV system. With these LPV systems, the control algorithms of LPV polytopic can be used in the control fields expediently.A LPV output feedback controller satisfying H_∞performance for ship course control is put forward, which is a gain scheduled control varying with ship speed. Furthermore, in order to get better performance for ship steering during ship speed varying in a large scope, the switching LPV controller for ship course control based on switching LPV control theory is put forward, through dividing ship speed scope into high and low scopes, designing the controllers in either scope, and switching the controller according to ship speed. Simulation results on 5446 TEU ship MMG model confirm that the two LPV controllers have good performance under disturbance.The LPV algorithm using the closed system poles assigned into circle region via state feedback is brought forward, which satisfy robust H_∞performance. The LPV algorithm is used in the controllers design for ship course and main engine integrated control, considering their effect on each other. Moreover, the LPV algorithm is also used in the indirect controller design for straight-line trajectory and main engine control. Furthermore, the shallow water controllers of steering and main engine are designed with the LPV algorithm, taking shallow water affection into account, so the integrated control is achieved for steering and main engine on shallow water. Simulation results make it clear that the designed controllers have good performance under wind, wave and flow disturbances and non-designed conditions.The control algorithms proposed in the dissertation should be greatly useful and helpful in integrating energy-saving control for ship, improving whole ship economical efficiency, and prolonging main engine life-span.