Research On EPS Of Pure Electric Commercial Vehicle Based On Neural Network Fuzzy PID Control

With the development of new energy technology,pure electric commercial vehicle is more and more widely used in the market,but its steering system is mainly electronic hydraulic power assisted system (EHPS).The structure of the electronic hydraulic power steering system is complex,and there will be energy conversion process when it works,so there are some disadvantages such as energy waste,low steering sensitivity and steering lag.Electric power steering system (EPS) has the advantages of zero pollution,energy saving,environmental protection,reliable performance and easy control,which has been widely used in passenger cars.In this paper,the application of EPS system in pure electric commercial vehicle is studied in order to improve the steering portability and sensitivity of the vehicle and adapt to the development trend of the whole vehicle electronics.The main contents of this paper are as follows:(1) A light pure electric commercial vehicle is selected as the research object,the power steering demand of the vehicle is analyzed,the system dynamics model is established,then the parameters of key components are calculated and set,and then the model is selected according to the parameters(2) Due to the wide range of change of pure electric commercial vehicle load,in order to meet the driver's assistance needs under different load conditions,the whole vehicle mass assistance characteristic curve is designed by comprehensively considering the three factors of vehicle speed,steering wheel torque and front axle load;at the same time,the control strategy of EPS system is studied,and the return,damping and assistance control strategies are respectively selected under different working conditions The EPS system can provide accurate assistance to the driver under various working conditions and different loads,improve the working efficiency of the system and reduce the driver's driving fatigue.(3) The neural network fuzzy PID controller is designed.The neural network fuzzy PID controller is used to control the actual current of the booster motor determined by the mass assist characteristic curve of the whole vehicle,and track the change of the current of the booster motor to form a closed-loop control.so as to improve the accuracy and efficiency of the current control of the booster motor.(4) The EPS system model of the whole vehicle mass assist characteristic curve and neural network fuzzy PID controller is established in Simulink,and the whole vehicle model is built in trucksim,and then the joint simulation is carried out.In trucksim,choose different road environment,establish the relationship between people,vehicles and roads,carry out road sense test,angle step test,double button line test and rapid moving line test under the condition of load change and different working conditions,and compare the simulation results with the simulation results of fuzzy PID controller commonly used at present.The test results show that the EPS system has a clear sense of road under the control of the whole vehicle mass assist characteristic curve and the neural network fuzzy PID controller,which is 10% shorter than the time when the fuzzy PID controller reaches the stability,the steering wheel torque is significantly reduced,and the system has better steering control stability,steering sensitivity,steering portability and obstacle avoidance ability.