The Research & Design Of The Control Unit Of Automobile Anti-Collision Warning System Based On Can-Bus

Focusing on the requirement of the freeway traffic in china, and the application situation and the development trend of automobile electronics technologies in china and abroad; synthesizing the principles of automobile engineer, automobile electronic technologies, communication technologies and advanced control technologies; according to necessity, feasibility, utility and economy, the paper puts out the scheme that designs the automobile anti-collision warning system (CWS) to produce the warning that can remind driver to take some corresponding measures, and reduce or avoid the collision when the vehicle falls into the danger of collision.The anti-collision warning system includes three sub-systems: sensor subsystem, center control sub-system, and information express sub-system etc. First, this paper analyzes three relative states between the host vehicle and the preceding vehicle during two vehicles drives on the freeway in the eye of microscopic, and establishes the applied mathematical model of the safety car-following distance. This paper presents an integrated comparison of the measurement project of three parameters of system model, for example, the distance between the host vehicle and the preceding vehicle, relative velocity, and the velocity of the host vehicle. The measurement project based on millimeter wave frequency modulated pulse-Doppler radar has been chosen to measure the distance between two vehicles, and the measurement project based on ten impulses Horae rotate speed sensor has been chosen to measure the host vehicle speed. The hardware and software design of the center control sub-system and information express sub-system are presented detailedly in this paper. This paper designs the information collecting unit that is the one of the center control sub-system to collect all information from sensors and communicate with control unit, which is the one of the center control sub-system too. Control unit judges the current safety situation of the host vehicle based on the mathematioal model of safety car-following distance, and provide the information of safety situation of vehicle for the driver by displaying instrument. The communication between all units is based on an advanced automobile communication technology-CAN bus serial communication technology,which has a good capability, to ensure the Real-time and reliability of system during the data exchange.Real-time, precision and reliability of system is fully considered. This paper uses a single chip Microcomputer of 8 bits MCS-51 series that is the control center of the system, and analyzes the work environment of system. According to the principle of the software and hardware of the controlling monitor system, during the course of the design of the software and hardware of system, the software and hardware antijamming technologies have been taken into account and applied. Finally, the experiment results prove that the automobile anti-collision warning system based on the CAN-bus can work steadily and reliably, judge the current safety situation of vehicle based on the mathematical model of safety car-following distance, and provide the information of safety situation of vehicle for the driver in time.The research of anti-collision warning system lives up to the development direction of the intelligent vehicle technology, the application of this system can guarantee vehicles safety, so it will help to increase transport efficiency and have a good prospect of application and economy.