Mekatronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/255
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Conference Object Citation - Scopus: 1Fuzzy Hybrid Systems Modeling With Application in Decision Making and Control(2012) Boutalis, Y.; Moor, T.; Schmidt, K.Hybrid Systems are systems containing both discrete event and continuous variable components. Many recent contributions address crisp situations, where ambiguity or subjectivity in the measured data is absent. In this paper, we propose Fuzzy Hybrid Systems to account for inaccurate measurements and uncertain dynamics. We present a strategy to determine the most appropriate control actions in a sampled data setting. The proposed approach is based on three basic steps that are performed in each sampling period. First, the current discrete fuzzy state of the system is determined by a sensor evaluation. Next, the future discrete fuzzy state is predicted for the possible control actions and the best action, in respect to desired continuous states, is selected. Finally, the decision is cross-evaluated by a limited horizon prediction of the continuous system variables. The proposed method is explained and demonstrated for a variation of the a well-known two-tank scenario. © 2012 IEEE.Conference Object Computation of Projections for the Abstraction-Based Diagnosability Verification(IFAC Secretariat, 2010) Schmidt, K.The verification of language-diagnosability (LD) for discrete event systems (DES) generally requires the explicit evaluation of the overall system model which is infeasible for practical systems. In order to circumvent this problem, our previous work proposes the abstraction-based LD verification using natural projections that fulfill the loop-preserving observer (LPO) property. In this paper, we develop algorithms for the verification and computation of such natural projections. We first present a polynomial-time algorithm that allows to test if a given natural projection is a loop-preserving observer. Then, we show that, in case the LPO property is violated, finding a minimal extension of the projection alphabet such that the LPO condition holds is NP-hard. Finally, we adapt a polynomial-time heuristic algorithm by Feng and Wonham for the efficient computation of loop-preserving observers.Conference Object Citation - Scopus: 12Applied Supervisory Control for a Flexible Manufacturing System(IFAC Secretariat, 2010) Moor, T.; Schmidt, K.; Perk, S.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 translate to discrete events from a practical point of view, including timing issues. The paper demonstrates how both, design and implementation, are supported by the open-source software tool libFAUDES.Conference Object Citation - Scopus: 2An Experimental Study of the Flexray Dynamic Segment(IFAC Secretariat, 2010) Schmidt, K.; Schmidt, E.G.; Demirci, A.; Yürüklü, E.; Karakaya, U.It is expected that the time-triggered FlexRay bus will replace the event-triggered Controller Area Network (CAN) for the high-speed in-vehicle communication in future automobiles. To this end, FlexRay provides a static segment for the transmission of periodic messages and a dynamic segment that is suitable for exchanging event-based (sporadic) messages. In this paper, we experimentally evaluate the operation of the FlexRay dynamic segment. In particular, we study how the maximum and average message delays are affected if the length of the dynamic segment, the message payload, the utilization of the dynamic segment and the priority assignment changes. Our experiments are carried out on a FlexRay network with 6 nodes. © 2010 IFAC.Conference Object Citation - Scopus: 12A Longest-Path Problem for Evaluating the Worst-Case Packet Delay of Switched Ethernet(2010) Schmidt, K.; Schmidt, E.G.In the recent years, the use of real-time Ethernet protocols becomes more and more relevant for time-critical networked industrial applications. In this context, this paper presents a method to compute the worst-case packet delays on switched Ethernet. Based on an evaluation of the packet delays at each switch port and the network topology, we construct a weighted directed graph that allows to find the worst-case end-toend packet delay by solving a conventional longest-path problem. © 2010 IEEE.