The Study And Test Bench Design Of Resistance-Loading System For Steering-By-Wire System

Steering-By-Wire System (SBW) is the future development direction of automobile steering system and the hardwire-in-the-loop test bench is essential equipment during the research. The performance of resistance-loading system, which is an independent module of hardwire-in-the-loop test bench, directly affects the accuracy of the hardware-in-the-loop bench. And it also plays an important role in SBW System test. Typically, design of resistance-loading system is the first step in the development of the Steering-By-Wire hardware-in-the-loop bench. So it is very significant to do a systemic study of the resistance-loading system for SBW.This thesis focused on the building of resistance-loading system for SBW. The following are the main aspects of thesis:Chapter one includes changes in the pattern of development of automotive electronics and the working principle of hardware-in-the-loop bench, and pointed out the necessity of designing the resistance-loading system. Analyzed the structure and working principle of domestic and international resistance-loading system. Based on this, the scheme of the resistance-loading system was determined.Chapter two is about the design of model and program. Some necessary models, including the full-car model, tire model and brushless DC motor model, were built. Then the whole scheme of the system is designed and the function of the system is proposed.Chapter three introduces the selection and design of the system hardware. According to the design scheme and function of resistance-loading system, suitable motor, sensor and main control chip were chosen. Then peripheral circuit of the micro-controller, receiving circuit of the sensor, the motor driving circuit, and the serial communication circuit were designed.Chapter four is the software design of the electronic control unit. Based on the designed hardware circuit the software for electronic control unit was programmed. The software mainly consists of the main program, the sensor sampling procedures, motor control procedures, and serial communication procedures and so on. After that, all the devices could work normally. Chapter five can be divided into two parts. One is man-machine interface and another is experiment. In the first part data transfer procedures, filtering procedures and user interface were developed by using LabVIEW. In the second part the resistance-loading system was proved to meet the design requirements by comparing the system output signal with the theoretical signal.