Research On Control Strategy Of EPS System For Low Speed Pure Electric Vehicle

With the progress of the automobile industry,consumers have put forward increasingly higher requirements for its safety performance,and also increased the demand for its operation stability and safety.Electric power steering system is the main battery as a power source,electric power,mechanical structure design,with the steering wheel torque and rotational speed as the main parameters of recognition,as the input signal,combining with the intervention of the control system,auxiliary machinery to assist,finally get good performance,the pros and cons of electric power steering system design will directly affect the accuracy and stability of the manipulation of the direction of people,to ensure road traffic safety,reduce accidents and safeguard the personal and property safety of the driver has the vital significance.When the electric power is involved,with the decrease of the speed,the steering force is gradually soft to ensure the light driving,making the direction more flexible;When the speed is too fast,appropriately increase the steering force,to ensure the stability of driving.At the same time,in terms of energy saving and consumption reduction,the energy consumption of the electric power steering system can be reduced by less than30% on the original basis,which can save natural resources to a certain extent,improve driving stability and improve environmental protection.Therefore,the research on this topic has a certain perspective.As the control strategy of electric power steering system directly affects the steering performance and safety performance of the vehicle,many domestic research institutions and institutes have carried out a large number of studies on the control system and control strategy of EPS,but there are still few studies on the control strategy of EPS for low-speed electric vehicles.With the development of low-speed electric vehicle and the expansion of its market share,its stability and steering control strategy have also become the focus of research.This paper takes a low-speed electric vehicle as the research objectt.The original power of the electric power steering system designed in this paper is the motor.The input signal is the steering wheel Angle,torque and vehicle speed.The performance of EPS steering system determines the safety and stability of driver operation and plays an important role in reducing traffic accidents and improving steering conditions.The core mechanism of the electric power steering system is the motor,the deceleration mechanism and the steering gear.The deceleration mechanism transmits the outputtorque signal of the motor to the power system through the deceleration and torsional increase to complete the assistance.When the car needs to turn,the torque sensor first plays a role.The torque signal extracted from the steering wheel is collected and transmitted down the data bus to the electronic control unit.The control system,combined with the torque,steering signal and real-time driving speed of the vehicle,will mechanically control the motor and issue instructions.The motor,combined with the input rotation moment,will determine the amount of auxiliary power to be generated.After calculation and analysis,the force is provided to meet the real-time control power steering.ECU determines different working conditions of vehicle steering through real-time information collected from torque sensor,speed sensor and steering wheel Angle sensor.ECU calculates control effects of target current control motor under different working conditions through algorithm.This topic selection and gear rack type steering gear,worm gear and worm drive way to their respective working principle is analyzed,through the control strategy of electric power steering system at home and abroad related literature,summarizes the research status at home and abroad,analyses the low-speed electric car power steering system and the selection of design,and establish the low-speed electric car power steering system dynamics model and MATLAB/Simulink simulation control model,put forward a kind of low-speed electric car power steering system dynamical characteristics curve and control strategy,whose effectiveness is verified by simulation analysis.