Research On Laser Scanning System And Technology For Obstacle Detection Of High-speed Railway

On the application background and requirements of real-time obstacle detection of railway tracks for high-speed trains, an obstacle detection & warning system for high-speed railway was designed based on the theory of active laser scanning. The detection system was mounted at the front of the train, so it could move with the high-speed train along the tracks. In this way, the system could emit a multi beam of plane scanning laser to realize the functions of scanning and searching on the assigned tracks region. At the same time, the system could detect and receive the optical energy reflected by the surface of the obstacles. Therefore it could judge whether some obstacles lay in this region and send a warning signal to the train management system. The system mainly consisted of four sub-systems: high-speed scanning system, high energy laser pulse emitting system, high sensitivity optoelectronic receiver module and information processing system.In this paper, the main research and design work fulfilled are as follows:1. The application requirements and theory of real-time forward obstacle detection for high-speed trains were analyzed; the system technological parameters were given. According to the analysis, a system design was present based on the high speed scanning laser.2. The high-speed scanning system was designed; the parameters of system mechanism and control were calculated. The optical route of laser scanning was analyzed. The theory research of the beam deflection on the scanning mirror was fulfilled. The relation formulas were announced about the deflection, location and mirror parameters. The polygon mirror was designed and machined, and the machining precision was evaluated. The reference parameters and operating circuit of high-speed motor were given.3. The theory analyses of effective operating distance were derived, which explained the interaction of various factors, such as: system parameters, environment variables and energy response. The energy response formulas of different target types were given separately, the reference numbers of formula parameters were recommended.4. The model selection and relative parameters of laser and optoelectronic receiver were recommended. The system of obstacle reflect optical energy collection and optoelectronic information processing was constructed based on the Avalanche Photodiode and integrated circuit. Meanwhile, the optical components of emitting and receiving system were designed.5. The experimental platform for system simulation was constructed. The operating theory and working effectivity were evaluated through the experiments on system sample. According to the experiment data, the system design was proved.