Research On Advanced Control Methods Of Electronic Throttle Valve

Throttle valve is a controllable valve located in the engine intake passage,and the rate of air flow into the cylinder is controlled by the angel of plate.The engine will adjust the air flow when vehicles run,so that the ratio of fuel to air is suitable,and the engine can work in a good condition.As a new type of throttle,the electronic throttle can achieve more accurate plate angle control compared with the traditional mechanical throttle,so as to achieve the optimal air-fuel ratio,further to improve the power performance and the economical efficiency of cars,and reduce the emission of pollutants.In this thesis,by modeling and analyzing electronic throttle system,some advanced control algorithms are proposed from different aspects to improve the performance of electronic throttle control system.The structural composition and working principle of electronic throttle are analyzed in this paper,and a second-order mathematical model is established.On this basis,the application of traditional PI control in electronic throttle is firstly studied.The results show that the PI control is difficult to meet the control requirements of high performance with friction and external disturbance.Accordingly,a compound control scheme based on disturbance observer is introduced,the nonlinear factors such as friction are taking as part of the lumped disturbance.Through the estimate and compensation of the disturbance,the compound control scheme not only deals with the influence of the friction,but also improves the anti-disturbance ability of the system.The simulation and experiment results verify the effectiveness of the proposed control scheme.Then,in order to optimize the control performance of electronic throttle,a control scheme based on model predictive control is designed,and a control law of rolling optimization is obtained by introducing the quadratic performance optimization index.Since the model predictive control is still a model-based control algorithm,when there is strong disturbance in the system,the precision of the prediction model will significantly decline,leading to poor control effect.In order to improve the anti-disturbance ability,the disturbance observer is introduced to observe the system disturbance,and the estimated value of the disturbance is added to the prediction model,so that the predicted output is closer to the actual output and the influence of the disturbance is weakened.Finally,considering the disturbance in the actual working process is not limited to constant or slowly varying disturbance,the model predictive control scheme based on high-order disturbance observer is studied,by introducing the high-order disturbance observer to estimate the high-order time-varying disturbance,further improving the anti-disturbance ability of the system.