What Is a Machine Fault Diagnosis?

Mechanical fault diagnosis is a technology to understand and master the state of the machine during operation, determine whether it is normal or abnormal as a whole or in part, detect faults and their causes early, and predict the development trend of faults. Oil monitoring, vibration monitoring, noise monitoring, performance trend analysis and non-destructive testing are the main diagnostic techniques.

Mechanical fault diagnosis is a technology to understand and master the state of the machine during operation, determine whether it is normal or abnormal as a whole or in part, detect faults and their causes early, and predict the development trend of faults. Oil monitoring, vibration monitoring, noise monitoring, performance trend analysis, and non-destructive testing are the main diagnostic techniques ^[1]

The United Kingdom established the Machine Health and Condition Monitoring Association in the early 1970s. By the early 1980s, it had done a lot of work in the development and promotion of equipment diagnostic technology and played a positive role in promoting it. The Watson Industrial Maintenance Company founded by the University of Manchester in the United Kingdom and the Friction and Wear Research Centre of the University of Swansea both have a high reputation in diagnostic technology research. In the field of nuclear power generation, the British Atomic Energy Research Institute has used noise analysis to monitor the furnace body and non-destructive testing of boilers, pressure vessels, and pipelines, which have played the role of the UK's fault data center. The UK still leads in friction and wear, automotive and aircraft engine monitoring and diagnostics ^[1]

The development of diagnostic technology in some European countries has its own characteristics. For example, the bearing monitoring technology of the Swedish SPM company, the infrared thermal imaging technology of the AGEMA company, the ship diagnostic technology in Norway, and the vibration and noise monitoring technology of the Danish B & K company are all different. Japan has an advantage in diagnostic technology in civil industries such as steel and chemical industries. Universities such as the University of Tokyo, Tokyo Institute of Technology, Kyoto University, Waseda University and other universities focus on basic theoretical research; while national research institutions such as the Institute of Mechanical Technology and the Institute of Naval Technology focus on the diagnostic research of mechanical basic parts; Systematic work has been carried out in the diagnosis of rotating machinery faults, and the "mechanical health care system" developed has played an effective role in the fault monitoring and diagnosis of turbo-generators ^[1]

The development of diagnostic technology in China began in the late 1970s, and the real start should begin in 1983 in Nanjing with the first special seminar on equipment diagnostic technology. Although it started late, after hard work, and the relevant government departments have repeatedly organized foreign diagnostic experts to give lectures in China, it has basically kept pace with foreign countries in this respect, and has been comparable to foreign countries in some theoretical research. China is very special in the diagnosis and research of some specific equipment, and has formed a group of its own monitoring and diagnostic products. Various industries across the country attach great importance to equipping key equipment with fault diagnosis systems, especially intelligent fault diagnosis expert systems, nuclear power stations, aviation departments and manned power systems in power systems, petrochemical systems, metallurgical systems, and high-tech industries. Aerospace Engineering, etc. The work is concentrated on large-scale rotating machinery fault diagnosis systems. More than 20 kinds of unit fault diagnosis systems and more than ten portable field data collectors that can be used for field fault diagnosis have been developed. Turbine generator and compressor diagnostic technology has been included in national key research projects and has been highly valued; while Xi'an Jiaotong University's "large-scale rotating machine computer condition monitoring and fault diagnosis system" and Harbin Institute of Technology's "unit vibration computer monitoring Troubleshooting System. " After years of research, the Equipment Diagnostic Engineering Center of Northeastern University has successfully developed the "Steel Rolling Mill Condition Monitoring and Diagnostic System" and "Fan Working Condition Monitoring and Diagnostic System", both of which have achieved promising results ^[1]

The signals that can be used for mechanical condition monitoring and fault diagnosis include vibration diagnosis, oil sample analysis, temperature monitoring, and non-destructive testing, and other technologies or methods are supplemented. Among them, the field of vibration diagnosis is the most extensive and theoretical.

With the development of computer technology, embedded technology and emerging virtual instrument technology, fault diagnosis devices and instruments have evolved from initial analog monitoring instruments to computer-based real-time online monitoring-fault diagnosis systems and microcomputer-based portable monitoring and analysis. system. This type of system generally has powerful signal analysis and data management functions, which can comprehensively record various information reflecting changes in the operating status of the machine, and achieve accurate fault diagnosis. With the development of network technology, remote distributed monitoring and diagnosis system has become a research and development hotspot ^[1] .