46 results about "Fuzzy petri nets" patented technology

Thousands of process and equipment measurements are gathered by the modern digital process control systems that are deployed in refineries and chemical plants. Several years of these data are historized in databases for analysis and reporting. These databases can be mined for the data patterns that occur during normal operation and those patterns used to determine when the process is behaving abnormally.These normal operating patterns are represented by sets of models. These models include simple engineering equations, which express known relationships that should be true during normal operations and multivariate statistical models based on a variation of principle component analysis. Equipment and process problems can be detected by comparing the data gathered on a minute by minute basis to predictions from these models of normal operation. The deviation between the expected pattern in the process operating data and the actual data pattern are interpreted by fuzzy Petri nets to determine the normality of the process operations. This is then used to help the operator localize and diagnose the root cause of the problem.

The invention provides a filling control method of semiconductor production lines, using a fuzzy Petri network technology to perform on-line filling control of the production lines. The method comprises the following steps of: establishing a filling fuzzy Petri network inference model, establishing an on-line filling mechanism of the semiconductor production lines, setting parameters of the fuzzyPetri network inference model, confirming a fuzzy inference condition warehouse set of the filling Petri network model according to uncertain events of an actual semiconductor production system, confirming an inference conclusion warehouse set of the filling Petri network according to the conclusion obtained in the confirmed inference condition, simultaneously gathering the inference rule set by abstracting and accumulating filling decision rules, establishing the filing fuzzy Petri network inference model, judging periodicity decisions by using the filing fuzzy Petri network inference model,starting the model once the accidents occur, and judging whether to modify and self-modify the filling plan or not according to the credibility of each conclusion warehouse. The method is simple in design process, easy in realization and good in robustness; meanwhile, the efficiency of the semiconductor production line is improved; the precognition capability is enhanced; and the integrity is correspondingly improved.

The present invention provides a numerical control equipment fault diagnosis method based on fuzzy Petri nets. The present invention proceeds from the basic principles of net theory, combines the characteristics of diagnostic problems, and takes the fault diagnosis of numerical control machine tools as an example to carry out a Petri net model in the field of fault diagnosis. At the same time, using the layered characteristics of fuzzy Petri nets, the relatively complex faults are subdivided layer by layer, thereby narrowing the scope of diagnosis, and finally improving the efficiency and practicability of fault diagnosis of CNC equipment diagnosis objects.