Hierarchical multitasking control of discrete event systems: Computation of projections and maximal permissiveness

Schmidt, Klaus Verner
Cury, José E.r.
This paper extends previous results on the hierarchical and decentralized control of multitasking discrete event systems (MTDES). Colored observers, a generalization of the observer property, together with local control consistency, allow to derive sufficient conditions for synthesizing modular and hierarchical control that are both strongly nonblocking (SNB) and maximally permissive. A polynomial procedure to verify if a projection fulfills the above properties is proposed and in the case they fail for a given projection an algorithm is proposed to find an extension of the set of events to be projected, in order to fulfill the sufficient conditions for SNB and maximally permissive hierarchical control.
10th International Workshop on Discrete Event Systems, WODES 2010, 30 Ağustos - 01 Eylül 2010


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SCHMİDT, KLAUS WERNER; Schmidt, Klaus Verner (2011-04-01)
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 obse...
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In this paper, a hierarchical and decentralized approach for composite discrete-event systems (DES) that have to fulfill multiple tasks is elaborated. Colored marking generators that can distinguish classes of tasks are used as the system model, and a colored abstraction procedure as well as sufficient conditions for nonblocking and hierarchically consistent control are developed. It is shown that the computational complexity for supervisor computation is reduced. A flexible manufacturing system example dem...
Applied supervisory control for a flexible manufacturing system
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This paper presents a case study in the design and implementation of a discrete event system (DES) of real-world complexity. Our DES plant is a flexible manufacturing system (FMS) laboratory model that consists of 29 interacting components and is controlled via 107 digital signals. Regarding controller design, we apply a hierarchical and decentralised synthesis method from earlier work in order to achieve nonblocking and safe closed-loop behaviour. Regarding implementation, we discuss how digital signals tr...
Marked-string accepting observers for the hierarchical and decentralized control of discrete event systems
Schmidt, Klaus Verner (2006-12-01)
The paper extends previous work, where we develop a control theory for nonblocking hierarchical control of decentralized discrete event systems (DES). The results are based on two technical conditions for the hierarchical abstraction: it has to be (i) locally nonblocking and (ii) marked string accepting. In this paper, we investigate the systematic construction of the hierarchical abstraction. Starting from an initial natural projection which need not fulfill (i) and (ii), we provide an algorithm to compute...
Hierarchical discrete event systems with inputs and outputs
Perk, Sebastian; Moor, Thomas; Schmidt, Klaus Verner (null; 2006-12-01)
We propose a framework for the hierarchical design of discrete event systems that addresses both safety and liveness properties. Technically, we build on a notion of inputs and outputs that is closely related to J.C. Willems' behavioural systems theory. We develop a structural admissibility condition that allows for abstraction-based controller synthesis similar to previous work on hybrid control systems. A key feature of our framework is an alternation of subsystem composition and controller synthesis that...
Citation Formats
K. V. Schmidt and J. E. r. Cury, “Hierarchical multitasking control of discrete event systems: Computation of projections and maximal permissiveness,” Berlin, Almanya, 2010, vol. 10, p. 98, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=80052003674&origin=inward.