Research On The Motion Control Of Wing-Diesel-Ship

Under the pressure of energy crisis and environmental pollution,the application of wind energy in ship propulsion,as renewable and clean energy,has gain greatly attention.The hard sail of wing shape,namely wing,with a broad range of available wind direction and high lift coefficient,becomes an important research subject.As the assistant force for the Wing-Diesel-Ship,wing force produces not only beneficial assisted driving force,but also negative lateral thrust.Moreover,the mutation of wing force disturbs to the ship motion.Therefore,further research of the motion control for the wing-assisted ship has important significance for the efficient use of the wing system,the safe and stable navigation of the ship.The aims of this dissertation are to provide maximum wing driving force and ensure ship course tracking for a 60000 t wing-assisted ship.The establishment of motion model for wing-assisted ship,the design of control strategy for wing and the optimization of control algorithm for ship course have been studied and analyzed systematically though theory,experiment and simulation.The details of these studies as follows:(1)Based on the wing's aerodynamic properties and wind tunnel test datas,the force and moment of the wing were analyzed.In order to improve the accuracy of the relative wind direction measurement,the measuring method of the wing mast's vector force based on the bending strain principle was proposed,which was verified by comparing the theoretical calculation and the experimental research of the wing.The dynamic response model of wing slewing system driving by hydraulic device was built to analyzing the static and dynamic characteristics though test research,and analysed by Matlab/Simulink.Therefore,the slewing motion model of the wing-assisted system was built,which can slew automatically by PD control algorithm,and the effectiveness of the model was validated by simulation.The wing force,which output from the model,could provide effective input to the wing-assisted ship motion control.(2)The ship motion model of three-freedom(sway,surge and yaw)was built with ship parameters and wind disturbance,and the effectiveness of the model was validated using Matlab/Simulink by comparing with the trial voyage data of the ship.Combined with the ship model and the wing model,the wing-assisted ship model with power fusion of "Wing-Propulsion-Manipulation" was established.The model has provided a theoretical basis for the research of the motion control of the wing-assisted ship.By simulation analysis of the ship motion with and without the effect of wing,the result shows that the direction of the lateral thrust of the wing is not necessarily same to the side thrust of the wind,which could used to select the optimal attack angle of the wing.(3)The effect of the resultant force to the static ship speed under different true wind speed and different relative wind angel was analyzed through the simulation of the ship motion when the force of the wing and air resistance of the ship were combined.Then the control scheme of the wing attack angle with maximum driving force to the ship was researched.The factors,such as the problem of the wind disturbance and wing stall,were combined to study and design the control strategy of wing attack angle including the filter of wind angle and the condition limit of wing.This control scheme and strategy achieved a closed-loop control of the wing-assisted system that adopted constant engine speed mode and constant ship speed mode in the simulation of ship navigation.The accuracy control of the attack angle verified the feasibility of the control strategy.The changes of the engine throttle scale and the ship speed were shown a significantally effect of energy saving by wing.(4)The ship autopilot were preliminary optimized based on the sliding mode control(SMC)algorithm to overcome the PID autopilot drawbacks,for instance lack of rapidity and accuracy of the course control with the effect of wing,using the wing-assisted ship motion model.Then an optimization study was performed to design the autopilot of the wing-assisted ship based on Back-Stepping SMC,Robust Adaptive SMC and Fuzzy Adaptive SMC respectively.Finally,simulation test verification on different control algorithms were conducted from the step response,sine tracking and wind disturbance conditions of the ship course by comparing step response overshoot,step response settling time,step static erro,sine tracking erro and the fluctuating value under disturbance.The results showed that SMC algorithm is better than PID,and the Fuzzy Adaptive SMC algorithm could provide the optimum control effect.