Research On Control Algorithm And Simulation Of Brake-by-wire System

The automotive braking system is an important component to guarantee the running safety, and it affects the safety performance of an automobile directly. The Brake-by-Wire system (BBW), integrating the by-wire technology and automobile braking system, replaces the conventional hydraulic brake actuator with power-driven units. Because of the well controllability characteristics and rapid responsibility of the power-driven system, it reveals a bright future to brake-by-wire system. In this thesis, the development history, research and present development status of The Brake-by-Wire system (BBW) technologies are introduced, and the comparison of the configuration, working principle, perform characters and the key technologies of BBW system are analyzed.The Anti-lock Braking System (ABS) is required to stop the vehicle by using the least brake time and the shortest distance under different road surface and climate conditions. The fuzzy control algorithm fits the control of braking process, which contains varying vehicle behavior and nonlinear system of the tire. And the fuzzy control also has an advantage of a higher robustness. Taking the wheel slip-ratio as a control object, the basic theory of fuzzy control is analyzed, the fuzzy controller of ABS is constructed, and the simulation of ABS characteristic is performed under three different road surface conditions. Combining the traditional fuzzy control and the classical PID control, the adaptive fuzzy PID control method is put forward, the simulation study is performed, and it enhances the application performance of fuzzy control method and PID control method greatly. Compared the simulation results of the fuzzy control algorithm to the PID control, the validity of the control algorithm is verified. A GA(Genetic Algorithm) based on-line parameter design method of ABS PID controlleris proposed, which is realized with Matlab/Simulink.Compared with the conventional braking system, the BBW system has lots of distinct advantages. It also has some particular performing characters and some key technology, which needs to be solved badly. With the improvement of control technology and electric technology, the BBW technology will definitely obtain the widespread application.