Research On Control Techniques Of Hybrid Electric Vehicle Brake System

Hybrid electric vehicle brake system which is composed by a mechanical brake system and a regenerative brake system is a kind of specific hybrid brake system. It has direct influences on several vehicle performance indexes. The control technique of hybrid electric vehicle brake system is not only very crucial to the multi-objective optimization of the vehicle in braking mode but also one of the key techniques in hybrid electric vehicle studying.Aiming at the multi-objective optimization problem of the hybrid electric vehicle in braking mode, this thesis focuses on a kind of advanced hybrid electric vehicle studying hybrid electric vehicle brake system control techniques and try to achieve the multi-objective optimization under the premise of ensuring the vehicle braking safety. The main contents of this study are as following:(1) To satisfy the requirements of the control techniques design, several systems are constructed including the brake system, transmission, vehicle dynamics and tire model. The constructed brake system is consisted of mechanical friction brake system which is one kind of electronic hydraulic brake system and regenerative brake system. The components of the regenerative brake system include permanent magnetic synchronizer motor, inverter and ultra-capacitor. The studied transmission system includes automatic manual transmission, main reducer and connected shafts. There are three freedoms are considered in the vehicle dynamics model such as longitudinal, lateral and yaw. And the Dugoff tire model is selected to express the dynamics of the tires.(2) A multilevel and coordinated control structure is constructed for the studied hybrid electric vehicle brake system. There are three levels in this structure:main controller, control allocation controller and actuator controller. The control objectives for the three controllers are also designed to facilitate the control algorithms design.(3) The control algorithms for the different controllers are developed based on the modern control theory. Among them, the main controller control algorithm is based upon the sliding mode control theory, and the control allocation method is used for the control allocation controller. The control algorithms which used for the actuators are also proposed.(4) The CAN bus technology is adopted to construct the information system for the hybrid electric vehicle brake system. Based on the SAE J1939 protocol, the communication protocol for the hybrid electric vehicle brake system is proposed. The proposed protocol is tested via an information systems test bench.The Off-line simulation platform for the studied hybrid electric vehicle is constructed using Matlab/Simulink software based on the developed dynamics models and control algorithms and the simulation techniques are studied. The simulation results shows that the designed control structure and algorithms can well satisfy the control demands of the studied hybrid electric vehicle multi-objective optimization problem.