An integrated knowledge representation scheme and query processing mechanism for fault diagnosis in heterogeneous manufacturing environments

Abstract

An integrated fault diagnosis system was developed for manufacturing complex products, e.g., automobile, that undergo a variety of production processes. The proposed global knowledge representation scheme is designed to consistently express such heterogeneous diagnostic knowledge in terms of the causal relations among relevant attributes across different processes. This scheme is unifying in that it reflects the fact that an effect for one causal relation may in turn be a cause for another along a chain of subsequent processes. In order to unify independent pieces of causal relation, specific attributes of machine-processed products in addition to the usual diagnostic signals such as noise and voltage of the machines. The accompanying probabilistic diagnosis mechanism can then produce an enhanced diagnostic accuracy over other existing schemes as it can simultaneously consider multiple causes of a fault along with their interdependency. The proposed diagnosis mechanism was implemented in a distributed computer environment to identify the functions and procedures required for its actual application.