Research On Grey Feedforward Compensation And Sliding Mode Control For The Fuel Viscosity Of Marine Main Engine

As a typical process control system in ship cabin automation,Ship fuel oil viscosity control system has been an important research topic in the field of ship automatic control.Currently,for the most of the ship engine room process control systems,conventional PID control is still the main control method.But,because of the complex structures of the main engine viscosity control system,and it has many complicated features such as nonlinear,time-varying,large delay and so on.It’s difficult for the viscosity control system to achieve the desired control effect using conventional PID only.This paper focuses on the modeling of ship fuel oil viscosity control system and the grey feedforward compensation and sliding mode control.The main contents are as follows:Firstly,after analyzing the structure of the ship main engine viscosity control system and working principle in detail,the mathematical model of the main link of the system including fuel oil heater,three-way control valve,mixed oil tank is established.Next,for the characteristics of ship fuel oil viscosity control system,a grey predictive feedforward compensation PID control algorithm based on the theory of Grey-Prediction is designed,then this algorithm is applied to the double-closed-loop main engine fuel oil viscosity-temperature control system.The simulation results show that the grey predictive feedforward compensation PID control algorithm has better ability to predict the main disturbance and good tracking performance compared than the conventional PID control algorithm.For the problem of anti-interference ability is not prominent using the algorithm above.A double-closed-loop main engine fuel oil viscosity-temperature control system based on grey predictive feedforward compensation and sliding mode variable structure compound control algorithm is designed.The simulation results show that this control algorithm has the advantages of small overshoot,fast response and the ability of strong anti-interference.Finally,the fuel oil heater has a problem of perturbation of the model parameters in the use of the process.But the simulation results further verify that the control algorithm based on the grey feedforward compensation sliding mode variable structure has a good ability to suppress interference,and the algorithm could reduce the influence of parameters-perturbation and has strong robustness.