Research On Modeling And Discrete-Time Sliding Mode Control Method Of Automobile Electronic Throttle System

The control accuracy of the traditional mechanical throttle is not satisfacting enough,resulting in the decrease of fuel economy and the increase of gas emissions.In recent years,the automotive industry has begun to use the electronic throttle to alleviate these shortcomings.The electronic control unit can calculate an optimal electronic throttle opening,and accurately control the valve blade to the target angle.It is of great significance for energy conservation and emission reduction.Therefore,improving the control performance of the automobile electronic throttle has an important effect on improving the performance of the automobile engine.The sliding mode control algorithm is a control algorithm with simple design and strong robustness,which is widely used in electronic throttle systems.Considering that the discrete throttle controller is limited by the sampling frequency,which may cause a decrease in control performance,a discrete sliding mode controller based on the discrete-time throttle system model will be designed in this paper.The structure and electromechanical characteristics of the electronic throttle system are first introduced in this article,and a mathematical model of the system is established.Based on this model,the discrete PID control algorithm is first studied under the influence of the friction,the spring and external disturbances,which is difficult to achieve a good control performance.Therefore,A discrete-time sliding mode control algorithm for the electronic throttle based on disturbance compensation is proposed.Spring,friction and external disturbances are considered as a lumped disturbance,and estimated by the delay estimation method.Compared with PID control,the proved control algorithm has a better dynamic performance and a stronger disturbance rejection ability,which is shown in simulation and experiment results.In order to alleviate the chattering problem in the discrete-time sliding mode control algorithm,the PIO observer is introduced,which plays a role of the low-pass filtering,and reduces the switching gain through the estimation and the compensation of disturbances.the effectiveness of this method is proved by xperiments and simulations.Considering that the throttle is greatly affected by the friction and the spring,the tracking accuracy of the electronic throttle is reduced.The Coulomb friction model and the spring model are identifies in this paper,and the design of the controller is based on the throttle model including the identified model.The throttle control system is designed with a discrete-time sliding mode control algorithm based on PIO and a feedback linearization.The better tracking accuracy of the control algorithm is shown in simulation and experiment results.In order to further eliminate the chattering problem,improve the dynamic response speed and the control accuracy of the electronic throttle.In this paper,a fast terminal sliding mode surface is designed,and the switching function in reaching law is replaced by a continuous non-smooth function.Finally,the effectiveness of the proposed method is given by simulation and experiment results.