Evaluation of diagnosability of failure knowledge in manufacturing systems

The authors focus on the diagnostic step of the error recovery process in manufacturing systems and develop theories for evaluating the diagnosability of failure knowledge in manufacturing systems. The theories are based on the action-error-feature data set, described previously by the authors (1989). The definition of one-error diagnosability and the necessary and sufficient conditions for multiple-error diagnosability are given. A simple matrix operation, called covering analysis, for testing the conditions is also presented. The methodology provides a qualitative measure for the embedded diagnostic knowledge in terms of the ability to diagnose the number of multiple simultaneous errors in the system. This provides the diagnosability of the model and the feasibility of the computation, because the covering analysis is simple and at most two analyses are required to determine multiple-fault diagnosability. A discussion of the results obtained and simple examples to illustrate those results are presented