Research On Traction Control And Virtual Simulation Of Electromechanical Brake For Light Vehicle

Electromechanical brake system (EMB) causes a revolution in vehicle braking system .It totally changes the traditional mode of the braking system and insteads the hydraulic pipelines of the braking system. Adopting EMB can bring many benefits, such as quick reaction, accurate regulation, reliable performance and less pollution. EMB has been the direction of vehicle braking system. Because of the hydraulic system, the traditional TCS can not react quickly and regulate accurately. In support of the EMB, TCS can solve these problems. With the application of virtual reality technology in vehicle simulation, we can create a 3D vehicle model and a virtual proving test in the computer, so it can avoid the disadvantages of all the conclusions interpreted and expressed in curves and data, which are lack of interactivity. The users can observe the vehicle model running on the virtual testing road, then evaluate its performance and improve the control logic.With the help of virtual reality technology on the research of driving wheels'braking control of TCS based on EMB, this thesis focus on the following sections. The vehicle virtual simulation platform is designed. The vehicle system dynamics module and the virtual environment module are created, and the communication between the two module is actualized. The driving wheels'braking control algorithm of TCS based on EMB is designed and compared. And the main research achievements are as follows:(1) Create the vehicle virtual simulation platformThe vehicle virtual simulation platform is divided into three modules, the vehicle system dynamics module, the virtual environment module and the communication module. This platform is extendable and reusable and is rightly designed. By using MATLAB/Simulink the dynamic vehicle system module is created to simulate the movement of vehicle. The mathematical model includes an engine model, a EMB model and a four-wheel car model with seven dof etc. The simulation result is used to estimate control logic, and to realize virtual simulation. By using VRML the virtual environment module is created. This module can real-time display the date from the dynamic vehicle system module making people obtain the realistic feeling and make the right evaluation to the simulation results. By using the Virtual Reality Toolbox of MATLAB the communication between virtual system and simulative system is actualized, so the system is prepared for simulation.(2) The driving wheels'braking control algorithm of TCS based on EMBBased on different driving conditions and the control aims of the controllers, the controller for brake pressure of driving wheels is designed using NN-PI control method. According to the correlative literatures, this thesis designs the three closed loops control method to control the motor of EMB. The control method can satisfy requirements according to the result of the simulation.(3) Simulation for driving wheels'braking control algorithm of TCS based on EMB using virtual simulation platformUsing virtual simulation platform for virtual simulation. The results are as follows:Virtual simulation platform, which can better reflect the actual situation, has good credibility. The virtual simulation results make up for the lack of true sense of the environment and the shortcoming of poor image .Users can not only analyse vehicle movement to experience the simulation process, but also clearly understand the specific vehicle parameters.The driving wheels'braking control algorithm of TCS based on EMB has a good control effect on low-μroad and split-μroad.