tailieunhanh - Monitoring and Diagnosing Manufacturing Processes Using Fuzzy Set Theory

Monitoring and diagnosis play an important role in modern manufacturing engineering. They help to detect product defects and process/system malfunctions early, and hence, eliminate costly consequences. | Du R. et al Monitoring and Diagnosing Manufacturing Processes Using Fuzzy Set Theory Computational Intelligence in Manufacturing Handbook Edited by Jun Wang et al Boca Raton CRC Press LLC 2001 14 Monitoring and Diagnosing Manufacturing Processes Using Fuzzy Set Theory R. Du University of Miami Yangsheng Xu Chinese University of Hong Kong Introduction A Brief Description of Fuzzy Set Theory Monitoring and Diagnosing Manufacturing Processes Using Fuzzy Sets Application Examples Conclusions Abstract Monitoring and diagnosis play an important role in modern manufacturing engineering. They help to detect product defects and process system malfunctions early and hence eliminate costly consequences. They also help to diagnose the root causes of the problems in design and production and hence minimize production loss and at the same time improve product quality. In the past decades many monitoring and diagnosis methods have been developed among which the fuzzy set theory has demonstrated its effectiveness. This chapter describes how to use the fuzzy set theory for engineering monitoring and diagnosis. It introduces various methods such as fuzzy linear equation method fuzzy C-mean method fuzzy decision tree method and a newly developed method fuzzy transition probability method. By using good examples it demonstrates step by step how the theory and the computation work. Two practical examples are also included to show the effectiveness of the fuzzy set theory. Introduction According to Webster s New World Dictionary of the American Language monitoring among several other meanings means checking or regulating the performance of a machine a process or a system. Diagnosis means deciding the nature and the cause s of a diseased condition of a machine a process or a system by examining the performance or the symptoms. In other words monitoring detects suspicious symptoms while diagnosis determines the cause of the symptoms. There are several words .