Research On The Key Technologies Of BCU Board Automatic Test System For High-speed EMUs

As a central control unit in the high-speed EMUs braking system, Brake Control Unit (BCU) is mainly responsible for the tasks such as braking force calculation, electro-pneumatic brake calculus control, antiskid control, air compressor control, communication, monitoring and troubleshooting, etc. The qualities of its performance parameters directly influence the reliability and security of the train running. Therefore, as a ruler of the BCU performance evaluation, the BCU automatic test system plays an important role in the BCU production, development and process of fault diagnosis. The topic researches on BCU automatic test system based on PXI bus. It is used to implement comprehensive tests of BCU board, and provide a powerful guarantee for its development, production and maintenance.The universality technology and parallel test technology is the development trend of today’s automated test system. In this thesis, we firstly make a deep study and exploration for these two key technologies, and expound their realization method. Then, on the basis of detailed analysis of the testing requirements, closely following the latest development trends of automatic test system, we build a multi-bus automatic test system based on PXI bus.The entire system hardware consists of PXI measurement modules such as PXI embedded controller, digital input and detection modules, analog input and detection modules, and so on. It also contains programmable power supply, signal conditioning adapter board, touch display, chassis and cabinet, etc. The system can realize the serial communication with BCU board and the measurement of basic electrical parameters as well as specific parameters of the BCU board, meeting the various indicators requirement. In hardware design, we focuses on the design principles and methods of10～30mA current circuit in analog input module. The test results show that10～30mA current generating circuit composed of AM422and TL431has good linearity and stability, and meets the needs of system. Signal conditioning adapter board design is also discussed in the paper, and the difficulty of design and the method of improving reliability are illustrated.The system software is designed with a number of technologies in the field of universal test and the field of parallel test. We use IVI technology to realize the instrument interchangeable, the TPS portable and reusable. The parallel test mainly uses the multi-thread technology to improve the efficiency of the test. The entire system realizes that the software has nothing to do with the underlying hardware interface. At the same time it ensures the independence between testing process and software, and meets the universality, scalability and portability requirements.The system completes full test of the BCU board after joint commissioning, and meets the design requirements.