Design And Implementation Of Rail Flaw Detection System

With the development of technology and the improvement of people’s quality oflife, safe, fast and comfortable rail transport are attracted more and more people’sattention. As a vital support of rail transport, a variety of injuries will be producedon rails in the long term transport process and that is a serious threat to traffic safety.Ultrasonic detector, as an important non-destructive method, has been widely used inthe transportation, mechanical manufacture, aerospace, defense industry and otherfields. But most of domestic existing ultrasonic detectors using single CPU toimplement the scheme. The software design is complex, code porting and code reuseare difficult, what’s more, it is difficult to maintain and upgrade the system.Therefore, this paper puts forward a solution of dual-CPU based on ARM and DSPportable ultrasonic rail flaw detection system that can realize the rail onlinecomprehensive detection, and it also has important theoretical significance andpractical value.The main content of this thesis is as follows：(1) Put forward a design idea of combining “ARM+DSP” hardware structureand embedded μC/OS-II operating system, TMS320C6713B and STM32F103ZET6are as the core to construct the hardware system so we can make full use ofadvantages of ARM in control and DSP’s powerful ability in data processing.(2) The ultrasonic emission device is improved so as to successfully launchexcitation pulse and ultrasound that has repetition frequency and adjustable voltageamplitude. Fully-differential circuit is used to drive A/D sampling circuit, which caneffectively reduce the electrical noise. FIFO is applied to the port between A/Dsampling output and DSP, so the data transmission efficiency is enhanced largely.Besides, Dual-port ARM is adopted to achieve the communication between DSP andARM, which will improve the performance of the whole system.(3) Wavelet transform is applied to eliminate the noise of echo signal so as toobtain valid signal, and the experimental results show that the noise in the echosignal are reduced greatly by using wavelet transform. μC/OS-II operating system issuccessfully transplanted to the STM32and the corresponding device driverprograms are developed here, besides, system tasks are divided so as to realize thecommunication between different tasks. (4) The rail flaw detection system has been tested and both level linearity errorand vertical linearity error of the test system meet the design requirements. Then0°,37°and70°probe are been tested in the WGT-1test block, experiments show thatthe rail defects can be detected by rail flaw detection system successfully.At last, the content of this thesis is summarized and further feasible researchproblems are discussed.