Iterative Sliding Mode Track Control Based On Adaptive Double Power Incremental Feedback

With the development of global economic integration,the trade volume between countries is increasing,and the development of international shipping is becoming more and more important.Therefore,the shipping industry had received widespread attention.By rationally planning the route and making the vessel sail according to the expected route,it can effectively improved the control efficiency of the vessel,reduced the sailing time of the vessel,extended the service life of equipment and reduced the energy consumption of the vessel.Therefore,it was significant to study the linear track control of ship.Aiming at the characteristics of underactuated surface ship motion:complexity,nonlinearity and vulnerability to external environmental factors,this paper used iterative sliding mode combined with double power approach law incremental feedback to propose a more rapid and stable non-linear iterative sliding mode algorithm,the algorithm can make the closed-loop system reach a progressively stable state without estimating external disturbances such as wind and current.In reality,the external environment was always changing when ship sailing at sea,and the control parameters of the double power incremental feedback were fixed,so the controller can't guarantee the optimality of the control parameters in different marine environments,the controller was not self-adapting.Therefore,this paper combined the sliding mode system with the neural network algorithm to improve the adaptability of the control system,so that the parameters can be automatically adjusted and improved according to external changes.By defining a feedback signal based on the ratio of the angular velocity of the ship's heading to the rudder angle,and using a neural network to realize the online optimization of the controller parameters,the controller's adaptability was improved,the ship's steering amplitude and the number of repeated steering were reduced,the service life of the ship was improved.The results show that the controller was not sensitive to external interference,the system can quickly stabilize,and had the characteristics of global asymptotic convergence.By comparing with the non-adaptive iterative sliding mode simulation experiment,the track and course deviation of adaptive ship control were obviously reduced,the buffeting of the rudder angle was weaker,which shows that the online optimization of controller parameters had a good effect.