Design of liveness‐enforcing supervisors via transforming plant petri net models of FMS
Chun‐Fu Zhong, LI Zhi-wu · Asian Journal of Control · 2010
Abstract This paper focuses on the deadlock prevention problems in a class of Petri nets, systems of simple sequential process with resources, S3PR for short. By structure analysis, we propose an approach that can transform a plant net model into a weighted S3PR (WS3PR) that is behaviorally equivalent to the plant model. The WS3PR is made to be live by properly reconfiguring its weight distribution such that its all strict minimal siphons are self‐max'‐controlled. The resulting WS3PR can serve as a liveness‐enforcing Petri net supervisor for the plant model after removing some idle and operation places. A live controlled system can be accordingly obtained by synchronizing a plant model and the places whose weights are regulated. This research shows that a small number of monitors is obtained, leading to more permissive behavior of the controlled system. Examples are used to demonstrate the proposed concepts and methods. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society