| To avoid the frequently or even ineffective steering for stable course in the situation of high ocean sea,in this paper the(Linear Active Disturbance Rejection Control)LADRC,which is model independent and have strong anti-high-frequency disturbance ability,is used for ship steering control.The main work of this paper includes:1.The nonlinear response model of ship motion and the wave disturbance model is designed to lay the foundation for the simulation and verification of the ship steering controller.2.To effectively avoid blind tuning of the observer bandwidth and controller bandwidth,the filtering characteristics of LESO and anti-disturbance characteristics of LADRC is analysed with changing bandwidths.Thus,the tuning principle and procedure can be derived when there is high frequency wave disturbance for the controller.Simulation verified the effectiveness of the chosen parameters and the determined controller showed a certain suppression ability against high frequency wave disturbance with satisfied precision of stable course.However,there still exist overshoot and the steering is not smooth enough.3.To eliminate the peak phenomenon of LESO,a modified tracking differentiator(TD)is added to curb the overshooting a Kalman filter is also added before the input of LESO to eliminate measurement noise.Comparative simulation experiment proved that the optimized controller possesses stronger filtering ability against high frequency wave disturbance of model frequency and measurement noise with decreased steering frequency and amplitude,more stable course output with smaller overshoot,which is basically satisfied to expectation.A stable course with less sailing resistance and protected rudder system can be achieved by designing an improved ship steering controller,through which the number of rudder response to high frequency wave disturbance can be decreased.In addition,it is of some theoretical and practical value for less emission,fewer sailing risks and more sailing comfort. |
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