Research On Sliding Mode Control For Fuel Quantity Actuator System

As the representative of internal combustion engine,diesel engine plays an important role in vehicle power.Improving the combustion efficiency of diesel engine and improving the economy of diesel engine have always been a hot topic of research.One of the main research objects at present is electronic fuel injection system of diesel engine,which is an important part of diesel engine.Electronically controlled VE pump is the oil supply system in diesel engine.It is improved from the traditional position distribution pump.Since the electronically controlled VE pump has less modification to the original mechanical oil supply system,it is more suitable for China’s current conditions.The fuel quantity actuator in the electronically controlled VE pump controls the amount of fuel entering the combustion chamber of diesel engine.It is an important control element in the electronically controlled VE pump.According to the target position given by the ECU,the rotary electromagnet drives the eccentric ball embedded in the control collar to control the opening degree of the fuel delivery hole,and finally achieves the purpose of controlling fuel injection quantity.In order to improve the response speed and anti-disturbance ability of the fuel actuator system in the electronic control VE pump of diesel engine,several advanced control schemes are proposed in this paper.The effectiveness of the designed controller is verified by simulation or experiment.Firstly,the basic structure and working principle of the oil actuator system are introduced.The mathematical model is established based on the analysis of nonlinear characteristics in the fuel actuator system.According to the established mathematical model,a composite control scheme based on extended state observer is proposed.This control scheme uses the extended state observer to estimate the external disturbance of the system,and introduces the disturbance estimation as feedforward compensation in the control law to suppress the disturbance.The simulation and experiment results demonstrate the effectiveness of the proposed control method.In order to further improve the anti-disturbance ability of the system,a sliding mode control scheme based on extended state observer is introduced in this paper.Sliding mode control has good robustness,and the estimation of disturbance by the extended state observer is used as a feedforward compensation term,which can not only guarantees the anti-disturbance ability of the system,but also reduces chattering phenomenon by choosing appropriate switching gains.Furthermore,this paper also introduces the design of nonsingular terminal sliding mode controller for the fuel actuator system based on non-linear sliding surface.The control method based on nonlinear sliding mode surface can make the system state error converge to the origin in finite time,and improve the convergence performance of the closed-loop system.Considering that the extended state observer can only deal with slowly time-varying disturbances,it can not accurately estimate periodic disturbances,such as sinusoidal disturbances.A non-singular terminal sliding mode control based on high-order sliding mode observer for the fuel actuator system is introduced in this paper.High-order sliding mode observers can accurately estimate different types of disturbances,such as periodic disturbances and slow time-varying disturbances,and the error of disturbance estimation can converge to zero in finite time.The simulation results verify the effectiveness of the algorithm.