Petri-net Controller for Pipe-line Transportation System

摘要

As for a pipe-line plant subjected to complex logical control specifications, an approach is proposed to generate the control codes via Petri net such that the plant is run as concurrently as possible. A PN model, called the plant net, is designed to represent the whole process of a pipe-line system. In this plant net, the tasks, including fluid transportation from one tank to another and cleaning tank, are represented by operational places, and level sensors in tanks are modeled by labels assigned with transitions. Further, conflict structures are used to describe the conflict relations among tasks due to the shared valves and pipes. By introducing a priority order in the transitions, an algorithm is presented to compute the control commands for valves based on this plant net. A beer filtration plant is taken as an example to illustrate the method.