Yazar "Gelen, Gokhan" seçeneğine göre listele

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    A New Approach for the Ladder Logic Implementation of Ramadge-Wonham Supervisors
    (IEEE, 2009) Uzam, Murat; Gelen, Gokhan; Dalci, Recep; Salihbegovic, A; Supic, H; Velagic, J; Sadzak, A
    In this paper, a new approach is proposed for the ladder logic code implementation of Ramadge-Wonham (RW) supervisors. The proposed method deals mainly with the assignment of actions (output signals) to the related states of RW supervisors. To-date there is no general method to solve this problem. In this paper, this task is accomplished by means of a very effective and easy to use technique. Once a RW supervisor assigned with actions is obtained, the conversion of this supervisor into ladder logic code is straight forward for PLC implementation. The effectiveness of the proposed method is demonstrated by means of a manufacturing system consisting of two machines and one buffer.
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    Novel analysis of Petri-net-based controllers by means of TCT implementation tool of supervisory control theory
    (MAEJO UNIV, 2010) Gelen, Gokhan; Uzam, Murat
    The control of discrete event systems (DES) has been widely studied in the past two decades. Finite-state automata (FSA) and Petri nets (PN) are the two principal modelling formalisms for this study. Supervisory control theory (SCT), based on language and FSA concepts, is a well established framework for the study of discrete event control systems (DECS). PN-based approaches to the control design have been considered as an alternative framework. In the PN-based control of DES, given an uncontrolled PN model of a system and a set of specifications, a PN-based controller consisting of monitors (control places) is synthesised to solve the problem. In general, forbidden-state specifications are considered. Another heavily studied specification is to obtain the live system behaviour (non-blockingness in SCT terminology) for a given PN model by computing a PN-based controller. Unfortunately, PN-based analysis tools cannot deal with uncontrollable transitions. Therefore, to date there is no general technique for the correctness analysis of the computed PN-based controllers. This paper proposes a novel and general methodology to carry out the correctness analysis for the computed PN-based controllers by using the TCT implementation tool of SCT. Three examples are considered for illustration.
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    The Concept of Postponed Event in Timed Discrete Event Systems and Its PLC Implementation
    (IEEE, 2010) Gelen, Gokhan; Uzam, Murat; Dalci, Recep
    Supervisory Control Theory (SCT) is one of the most important frameworks for establishing formal discrete event control systems. Despite some difficulties, the programmable logic controller (PLC) implementation of supervisory controllers obtained from SCT for untimed systems is well established within the literature. However, there is no general and easy to use method for obtaining supervisory controllers with time delay functions. In order to address this need, in this paper the concept of postponed event is proposed for introducing the time delay functions within untimed automata. Postponed event pe is defined as the shifted version of an event e on the time axis by a deterministic time delay value. Postponed event is a general, easy to use and practical method for PLC implementation of supervisory controllers with time delay functions. Supervisory controllers can be obtained as in untimed systems by using SCT framework with the assumption that postponed events are taken into account as if they are normal (untimed) events. Then they are refined at the implementation stage by the assignment of time delay values to respective events. The implementation of postponed events can be realized by using on delay timers, off delay timers or pulse timers of PLCs. The applicability of the proposed method is demonstrated by means of an example.
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    Timed Transition Automata and Their Ladder Logic Implementation
    (IEEE, 2009) Uzam, Murat; Gelen, Gokhan; Dalci, Recep; Salihbegovic, A; Supic, H; Velagic, J; Sadzak, A
    In this paper, a simplified version of timed automata, called timed transition automata (TTA), is proposed. TTA are an extension of untimed automata and are obtained by assigning integer time delay values to events. The proposed TTA are very useful for programmable logic controller (PLC) implementation of supervisory controllers with time delay functions. Supervisory controllers are obtained as in untimed systems by using Ramadge-Wonham framework and then they are refined by the assignment of time delay values to respected events. The implementation of timed transition is realized by using on delay timers of PLCs. The applicability of the proposed method is demonstrated by means of a manufacturing system consisting of two machines and one buffer.