A CONTROL MODEL FOR DETECTING DEADLOCKS IN AN AUTOMATED MACHINING CELL

Process interactions in concurrent manufacturing systems can result in deadlocks which are difficult to detect during the controller program design stage. This paper reports on the application of a Control Model for detecting deadlocks in an Automated Machining Cell consisting of a CNC lathe and a service robot. The Control Model is generated from a list of Programmable Logic Controller events using the theory of Petri Nets. The model is tested for deadlocks that could possibly occur due to the concurrent nature of activities in the cell. The applicability of the model is demonstrated on an Automated Machining Cell installed in the Manufacturing Automation Laboratory at Rutgers University. The results show a promising perspective of Control Model applications in debugging Programmable Logic Controller programs.