Research On Temperature Field Detection Sysytem For High-speed Train Axle

Railway plays an important role both in the process of national economicdevelopment and in people’s daily life. It is the backbone or main force of our country’stransport industry. Along with the ‘speed boost’ of China’s railways, safety and securityof the railway transport is also facing new challenges. As one of the most importantfactors, the axle temperature of the train has been recognized as one of the mainindicators of the railway safety. Train axle temperature field online detection system isdeveloped to sense the temperature of train axle on a running train, which can contributeto the safety in train operations.The temperature of train axle detection system in existence usually presents thetemperature directly, but can’t paint the images of the distribution of temperature fieldof the train axle. The temperature of train axle detection system in this paper actuallycan be considered as a high-speed thermal infrared imager for detecting the temperatureof train axle, which can intuitively presents the infrared image of the train axle. Basedthe principle of Infrared Radiation Temperature Measurement, the scenario of thissystem is to use a PbSe infrared linear array detector to detect the temperature of thetrain axle in vertical direction while the train steers in a horizontal direction. By this way,the detection can form a2D infrared image of the train axle.This system consists of slave computer used for gathering signals of the train axlesand host computer for generating infrared images and further image processing. Whenthe train is on operations, the Infrared Linear Array Detector will capture the infraredradiation of the train axles through optical system. As soon as those sensing componentsof the Infrared Array Detector receive the infrared radiation and turn into electricalsignals, those signals would be amplified by the readout circuit on radiation detectors.Based on the speed signals collected, the system will determine the start time andthe acquisition speed of the data acquisition board. All the data will be stored in SRAM.After the train passing through, host computer will connect to slave computer. The datastored in SRAM will be transferred to host computer via Ethernet, thus acorrespondence between voltage and gray scale is built, from which Gray Scale ofImage is formed although a series of procedures need to done to enhance the pictures,for instance, Detector Non-uniformity Correction, Gray Histogram Equalization andPseudo-color coding. The final image we see is Infrared Thermography.Based on Visual C++, this article presents us with data acquisition board speedcontrol procedure, data communication procedure and image processing program.Through calibrating the system, the correspondence between the Gray Scale of Imageand axle temperature of the train is built, and infrared imaging of the axle temperaturecan be achieved by this system. This train axle temperature detection system has passed the final test. Both therange of temperature and the accuracy of the system can meet the requirements of thesystem. And the system can achieve the infrared images of the things in fast motion, forexample, the train axle and so on.