Time templates for discrete event fault monitoring in manufacturing systems

The input and output signals of automated manufacturing systems can be characterized as observed time functions of discrete events. Fault monitoring is the online analysis of the process observations to determine if they correspond to a specification of correct process operation. In this paper, we describe a new fault monitoring method, called template monitoring. Template monitoring overcomes several limitations associated with methods based on traditional discrete event process models. The template monitoring method is easily distributable, and is suitable for monitoring concurrent event relationships. We derive analytical results for generating templates from timed automaton models and describe the use of templates for real-time monitoring and diagnostics.