Sequence controller synthesis for automated guided vehicle systems Using ordinary Petri nets

An approach is proposed to design the programmable logic controller (PLC) for an automated guided vehicle system (AGVS), using ordinary Petri net (PN). First, it models an AGVS as a plant PN. Second, the PN supervisor is designed to firm a closed-loop PN by augmenting the plant PN. Specifically, it adds control transitions to the plant PN to control the wiring loops that are to make the vehicles stop for loading and unloading. The resultant closed-loop PN of an AGVS can be analyzed by PN theories. Lastly, it can translate a closed-loop PN into a ladder diagram that can be performed by a PLC. A laboratory AGVS is used to illustrate the present method.