Mekatronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/255
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Article Citation - WoS: 17Citation - Scopus: 20State Attraction Under Language Specification for the Reconfiguration of Discrete Event Systems(Ieee-inst Electrical Electronics Engineers inc, 2015) Nooruldeen, Anas; Schmidt, Klaus WernerIn this note, we study a particular setting for the reconfiguration of discrete event systems (DES) that is applicable to the control of reconfigurable manufacturing systems (RMS). We consider DES that can operate in different configurations and we are interested in the realization of configuration changes. Different from previous work, we intend to reach a set of plant states where a new configuration can be started in a bounded number of transitions and at the same time fulfill a behavioral specification before starting the new configuration. To this end, we introduce the concept of weak attraction under language specification (WALS) and derive necessary and sufficient conditions for its verification. Using WALS, we propose a polynomial-time algorithm for computing a supervisor that performs the described configuration changes. We demonstrate the applicability of our method using a workcell of an RMS.Article Citation - WoS: 5Citation - Scopus: 5Optimal Supervisory Control of Discrete Event Systems: Cyclicity and Interleaving of Tasks(Siam Publications, 2015) Schmidt, Klaus WernerA substantial number of tasks in production systems are executed in a repetitive, cyclic fashion. Specifically, production systems run different production cycles of different products as well as different instances of the same production cycle. In this paper, we consider the optimal control and interleaving of such production cycles in a supervisory control framework for discrete event systems (DESs). That is, different from other approaches, our work is based on a behavioral specification of each production cycle. First, we adapt an optimal control approach for DESs, in order to optimize the operation of individual production cycles. Second, we employ the interleaving composition to design a supervisor that enables the simultaneous execution of different production cycles. Combining both results, we can further determine the maximum number of production cycles that can be executed simultaneously on a given production system.Article Citation - WoS: 54Citation - Scopus: 74Maximally Permissive Hierarchical Control of Decentralized Discrete Event Systems(Ieee-inst Electrical Electronics Engineers inc, 2011) Schmidt, Klaus; Breindl, ChristianThe 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.