Vehicle Intelligence Parking Brake And Hill-start Assist Control System Research

With the development of electronic technique, modern vehicle tends to be electronization and more and more intelligent. In the field of parking braking, traditional parking brake system, electric parking brake system and intelligent parking brake system appear successively during these decades. Intelligent parking brake system is the tendency of development in the future. It simplifies the operation processes of the driver greatly and because of possessing electronic control unit, it can be integrated with vehicle control unit, cooperating with other vehicle electronic systems then improve the security and driving comfort when the vehicle is parking.Firstly, this paper comes up with the total design proposal by analyzing the structure of the traditional parking brake system and the working principle of the electric parking brake system. What’s more, according to the functional requirements of the parking brake system, the following three main functions are also determined, such as intelligent parking and hill start assist as well as emergency brake, In the meantime, a new method of mass evaluating is proposed in this paper to adjust the brake force and avoid the problem of running before start and coasting in the hill which has great sense of improving the vehicle’s starting speed and ride comfort.Secondly, by analyzing the process of traditional parking brake system, vehicle kinematic parameters need to be collected to judge the parking brake intention of the driver, and a control strategy is proposed for intelligent parking brake system. Based on simple suspension model, the process of parking brake and start-go of the vehicle are analyzed, the variation of pitch angle of the vehicle body is then confirmed to be as the signal to know whether the car will start to go. Meanwhile, by analyzing the traction forces exerted on the vehicle, it is obtained that with the increment of the drive torque passed to the driving wheel how the ground parking brake force changes during the starting process and then an accurate moment to release the parking brake force is determined. Then mass estimating module strategy as well as the hill-assist-start module control strategy. are established based on the above theoretical analysis when the vehicle is runningAnd then, the co-simulation model is established using Carsim and Matlab/Simulink to finish the whole verification of the theory together with the functions of the intelligent parking brake system. According to the results of the simulation module, the threshold of modification of the vehicle mass in the mass estimating module as well as the threshold of the variation of declivity corresponding to the moment releasing the parking brake force in the hill assist start module are acquiredAnd then the design of on-vehicle experimental scheme is achieved, and by means of reviewing the regulations about parking brake, the reduction ratio of the manipulating mechanism of parking brake system of the test car and actuating electric motor selection as well asthe arrangement of motors and sensors are designedFinally, in accordance with the control strategies, the compilation of the algorithmic program of each of the function modules are finished under the environment of Code Warrior, and the program is then downloaded to the intelligent parking brake system controller, and debugged. A proper test field is chosen to finish the road test, and the experimental results are analyzed and processed, and ultimately the total design and verification of the parking brake system is accomplished.