Maximally Permissive Hierarchical Control of Decentralized Discrete Event Systems

SCHMİDT K. W., Breindl C.

IEEE TRANSACTIONS ON AUTOMATIC CONTROL, vol.56, no.4, pp.723-737, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 56 Issue: 4
  • Publication Date: 2011
  • Doi Number: 10.1109/tac.2010.2067250
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.723-737
  • Keywords: Decentralized control, discrete event systems, hierarchical control, large-scale systems, maximal permissiveness, supervisory control, SUPERVISORY CONTROL, EQUIVALENCE, CONSISTENCY
  • Middle East Technical University Affiliated: No


The subject of this paper is the synthesis of natural projections that serve as nonblocking and maximally permissive abstractions for the hierarchical and decentralized control of large-scale discrete event systems. To this end, existing concepts for nonblocking abstractions such as natural observers and marked string accepting (msa)-observers are extended by local control consistency (LCC) as a novel sufficient condition for maximal permissiveness. Furthermore, it is shown that, similar to the natural observer condition and the msa-observer condition, also LCC can be formulated in terms of a quasi-congruence. Based on existing algorithms in the literature, this allows to algorithmically compute natural projections that are either natural observers or msa-observers and that additionally fulfill LCC. The obtained results are illustrated by the synthesis of nonblocking and maximally permissive supervisors for a manufacturing system.