Study On The Hill-start Assist Of Automotive Electronic Parking Brake System

Electronic technology in vehicle integrates auto technology with electronic technology. As technology of auto and electron developing, the application of electronic technology to vehicle becomes more and more extensive and the electronic grade of vehicle becomes higher. The system of Electronic Parking Brake (EPB) is a type of the automobile's braking system controlled-by-wire, is also the development direction of the vehicle's brake system. It replaces the pull-tight-wire and brake equipment of traditional hand-brake system by the wire, replaces the traditional brakes by electronic brakes, which controlled the magnitude of vehicle parking-strength and dynamically distribute parking-strength on each wheel combined the car environment of condition with the electronic control unit(ECU). This EPB has the function of Hill-start Assist and intelligences of parking/relief function. This system is the innovation of the vehicle parking system. This text focuses on the Hill-start Assist of Electronic Parking Brake system. A Hill-start simulation model was established. The parking brake force and the clamp force of brake have got through the simulation analysis, which are very important and could support the development of EPB.The paper introduces the background of development and application of EPB at home and abroad, the advantages and disadvantages of EPB, the development tendency of EPB. Taking Magotan as an example, which is produced by the Changchun FAW-Volkswagen Automotive Company,the paper also presents the basic operation principle and component elements of EPB and its 4 functions. Conditional parking brake system and the EPB are compared.On the base of analyzing relevant national standards, the systematic function of EPB is designed, and whole scheme of the design is described in detail.It abandoned the traditional parking brake actuator, uses two motors on the rear brake caliper to the implementation of the parking brake. A brief description and analysis of the EPB's actuators were given.Through stress analysis of car in the process of uphill start, we obtain the questions on which should pay attention. Then the hill starting dynamics formulas are established, which is based on the analysis of the model and the control method of clutch and the result of hill-start resistance identification.At last, this paper uses the Matlab/Simulink software to set up engine model, clutch model and a whole vehicle simulation model, which is based on the relevant data of the car. Through the simulation, the parking brake force and the clamp force of brake are obtained.