Monitor design with multiple self-loops for maximally permissive supervisors

ISA Trans. 2016 Mar:61:129-140. doi: 10.1016/j.isatra.2015.12.016. Epub 2016 Feb 5.

Abstract

In this paper, we improve the previous work by considering that a control place can have multiple self-loops. Then, two integer linear programming problems (ILPPs) are formulated. Based on the first ILPP, an iterative deadlock control policy is developed, where a control place is computed at each iteration to implement as many marking/transition separation instances (MTSIs) as possible. The second ILPP can find a set of control places to implement all MTSIs and the objective function is used to minimize the number of control places. It is a non-iterative deadlock control strategy since we need to solve the ILPP only once. Both ILPPs can make all legal markings reachable in the controlled system, i.e., the obtained supervisor is behaviorally optimal. Finally, we provide examples to illustrate the proposed approaches.

Keywords: Deadlock prevention; Flexible manufacturing system (FMS); Petri net; Self-loop; Supervisory control.

Publication types

  • Research Support, Non-U.S. Gov't