Design Of Monitoring And Diagnostic System For Infrared Hotbox Detector And Audio Channel

The infrared hotbox detection system is applied widely in railway network and routine maintenance is still mostly achieved by manual inspection. Staffs from different departments have to troubleshoot at the same time when fault occurs. Fault cause is not found timely and it brings potential risk to running trains. Monitoring and diagnostic system is developed to solve this problem. It monitors work state of the infrared hotbox detection system in real time, and determines that infrared hotbox detector or audio channel causes the fault. It clarifies the responsibility between train and communication departments and improves the operating efficiency.Firstly, the overall scheme of monitoring and diagnostic system is proposed. The system is illustrated in terms of scheme analysis, functional structure, and operating principle. Then, the schemes of monitoring terminal, analytical and diagnostic equipment and monitoring and diagnostic platform are introduced.Secondly, frequency measurement subsystem based on FPGA is designed. Frequency measurement subsystem is developed and software and hardware of the subsystem are implemented. Then equal precision measurement theory, distortion data distinguishing method, and frequency measurement flow are illustrated. Next, frequency measurement subsystem is tested. Monitoring and diagnostic system determines whether the fault has happened according to frequency of audio signal.Then, fault diagnosis module based on signal feature is designed. Audio monitor subsystem is developed and software and hardware of the subsystem are implemented. Next, methods of amplitude measurement and data length acquisition are proposed. Monitoring and diagnostic system determines whether the fault has happened according to amplitude and data length of audio signal. After that, work steps of fault diagnosis are described.Next, fault prediction module based on grey system theory is designed. Fault prediction module is developed and software of the module is implemented. After that, methods of state prediction and model checking are described. Then simulation experiment is made to predict amplitude and frequency shift of audio signal and to determine whether the fault is going to happen.Finally, monitoring and diagnostic system is debugged and the result satisfies design requirement. Performance of monitoring terminal, analytical and diagnostic equipment, and monitoring and diagnostic platform is tested respectively. In addition, fault removal scheme is designed and intelligent power is developed to remove the fault caused by modem crash.