Theory of chaos based techniques for process monitoring

This paper presents an overview of different chaos theory based techniques that may be employed for process monitoring; specifically for monitoring of manufacturing processes. Most process monitoring systems involve estimating certain unknown state variables from the known sensor measurements. This estimation scheme requires mathematically relating the measured time-series data (TSD) from sensor signals to unknown state variables. In order to systematically establish this relationship, knowledge of the process dynamics is essential. Since the dynamics of many manufacturing processes is very likely to be nonlinear, the use of chaos theory is relevant for process monitoring. This paper describes various chaos theory based techniques employed in process monitoring systems.