Research On Longitudinal Active Collision Avoidance Control Method For Electric Vehicle

With the development of society and the improvement of people’s level,various types of vehicles are increasing day by day,which is the chief culprit of traffic safety problems.Therefore,the design and application level of security technology must be ensured to minimize the security risks.Among them,the vehicle longitudinal active collision avoidance control system is a new type of technical system,which has been developed and applied in theoretical research and practical application.However,this technology is not mature enough,and it needs further in-depth study.This research takes vehicle safety as the starting point,takes four-wheel independent drive hub electric vehicle as the object to carry out systematic research and analysis,adopts a new safe distance model and upper model predictive tracking control algorithm,solves the design and application problems of longitudinal active collision avoidance system,defines the design concept and implementation method of relevant key technologies,and forms a relatively scientific and perfect design system to provide valuable reference for automobile design.Complete the following research tasks:(1)Using Car Sim2019 software as a tool to build a dynamic model,and complete the design and development of vehicle structure,transmission system,braking system,tires,self-propelled road and other models.(2)In this paper,two longitudinal safe distance models are established according to the static and moving state of the preceding vehicle,and the characteristics of drivers are taken into account,which is more in line with the driving specifications of drivers.When the front vehicle is in a stationary state,the design and development of the safe distance model is completed based on the principle of dynamics technology.When the front car is running,the specific design task of the safety distance model is completed by combining algorithm tools such as constant time headsway(CTH)and variable time headsway(VTH)Then,the reliability and stability of the model are analyzed and verified.Finally,TTC-1 is used to verify the safety of the two safety distance models.(3)According to the model predictive control theory and the longitudinal safe distance model of two vehicles,the model predictive upper controller is established,and the upper controller model is built in Simulink to establish the space equation which can reflect the relative motion state of vehicles.The linearized equation is converted into discrete form.The vehicle state variables,such as acceleration,vehicle distance and vehicle speed,are controlled within a reasonable range by constraint conditions.The constrained optimization problem is transformed into a quadratic programming problem and solved.According to the principle of PID control,a lower controller model is established,which includes two elements: calculation and distribution of braking force.PID calculates and analyzes the comprehensive braking force of the system,and completes the scientific distribution of the total braking force in combination with the vertical load of the vehicle.(4)This paper adopts a simplified model of permanent magnet synchronous motor as the driver of electric vehicle.Through the joint simulation of Car Sim2019 and Simulink,the driving of electric vehicles is realized.Finally,a summary of the full text is made,and the prospect of the full text is made.