Fuzzy assignable cause diagnosis of control chart patterns

Control chart patterns, besides determining the presence of assignable causes, also provide hints on the nature of assignable cause present. But relating the patterns exhibited on the control chart to assignable causes is an ambiguous and vague task especially when multiple patterns co-exist. In this work, a fuzzy rule based system is developed for Xmacr chart, based on a chart pattern-cause relationship network, to resolve the uncertainties in identifying the control chart patterns and relating them to assignable causes.