Research On Modeling And Disturbance Rejection Control For Electronic Throttle Valve System Of Diesel Engines

The traditional automobile throttle is connected to the accelerator pedal in the driving room by wire rope and lever.Throttle valve opening is controlled by the driver's foot pedal stroke.That is to say,the output power of the engine is changed by changing the section area of the throttle inlet channel.Electronic throttle valves have also been gradually applied to diesel engine control systems in order to improve the exhaust gas recirculation(EGR)rate of diesel engines under various operating conditions,so as to improve the overall dynamics,fuel economy and comfort of diesel vehicles.Meanwhile,there are external disturbance in the diesel electronic throttle due to input voltage fluctuation and other factors,as well as nonlinear characteristic due to friction nonlinearity and return spring nonlinearity.These disturbance and nonlinearity often make it difficult to obtain satisfactory closed-loop performance.For this reason,through modeling and analysis of these factors,this dissertation discusses how to suppress disturbance and compensate nonlinearity.In order to improve the performance of the diesel electronic throttle system.The main research contents include the following parts.First,the mathematical model of diesel electronic throttle control system is established.Then the generalized proportional integral observer(GPIO)based backstepping control algorithm,the traditional sliding mode control(SMC)algorithm and GPIO based SMC algorithm are designed to enhance the disturbance rejection capability of systrm.In order to build a mathematical model,the working principle and structural characteristics of diesel electronic throttle is analyzed firstly in this paper.The influence of the return spring torque and friction torque on the system performance is emphatically analyzed,which can be estimated and compensated as disturbance like input voltage fluctuation.Second,the state observer has to be designed because the angular velocity of the electronic throttle is not measurable.The GPIO introduced in this paper can observe the angular velocity and estimate the lumped disturbance in polynomial form.Then,for the position control of diesel electronic throttle system,compound controller is designed by backstepping control method.In order to further improve the disturbance rejection capability of diesel electronic throttle system,the traditional SMC algorithm and GPIO based SMC algorithm are introduced.The traditional SMC resists external disturbance by discontinuous switching control input.When the disturbance is too large,the switching gain in the SMC needs to be increased accordingly.The large amount of discontinuous control will cause chattering problem.In this paper,the GPIO is designed to estimate and compensate the lumped disturbance of the system.The switching gain of this composite controller is only required to be designed greater than the bound of disturbance estimation error rather than the bound of the disturbance,which can substantially alleviate the chattering problem.Finally,the effectness of the designed algorithms is verified by simulation and experiment.