Colored timed Petri net based statistical process control and fault diagnosis to flexible manufacturing systems

The quality consistence and machines' utilization of a flexible manufacturing system (FMS) strongly depend on the statistical process control (SPC) and the correct fault diagnosis of equipments. An FMS can be modeled by the Colored Timed Petri Net (CTPN). However, the CTPN models of most FMSs lack the activities of the statistical process control (SPC) and fault diagnosis, and they lead to the incomplete FMSs' CTPN models. In this paper, the CTPN-based SPC and fault diagnosis models are proposed to model the FMSs' SPC and fault diagnosis behaviors. Since the models depend on the measured data from the inspection machines and the sensors' data from the devices, the CTPN-based SPC and fault diagnosis models can be incorporated into the production CTPN models to give a complete model of FMSs' activities. It will be shown the CTPN-based fault diagnosis is easy to model, and the results are straightforward.