Browsing by Author "Schmidt, Klaus"

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Citation Count: Khalid, Harith M.; Schmidt, Klaus. "Abstraction-Based Modeling and Control For Reconfigurable Machine Tools (RMT)", Engineering and Technology Symposium, 2014.
Abstraction-Based Modeling and Control For Reconfigurable Machine Tools (RMT)
(2014) Khalid, Harith M.; Schmidt, Klaus
Citation Count: Kart, Bora Eser; Schmidt, Klaus. "Computation of Reduced Diagnosers for the Fault Diagnosis of Discrete Event Systems", Engineering and Technology Symposium, 2014.
Computation of Reduced Diagnosers for the Fault Diagnosis of Discrete Event Systems
(2014) Kart, Bora Eser; Schmidt, Klaus
Many complex systems in different areas such as manufacturing, telecommunications or transportation can be modeled as discrete event systems (DES). In this paper, we consider the fault diagnosis for DES which is concerned with detecting fault occurrences in a DES within a bounded number of event occurrences by a diagnoser automaton. Hereby, such diagnoser is able to observe a subset of the system events and the maximum required number of event occurrences until a fault detection is denoted as the worst case detection delay (WCDD). The main contribution of the paper is an approach for reducing the number of required observations for fault diagnosis without increasing the WCDD. As a result, it is possible to determine a diagnoser with a small size which is essential in practical applications. We first develop an algorithm for computing the WCDD and then adapt an approach for the reduction of the observable event set in order to obtain a reduced diagnoser. The application of our method to a communication system example demonstrates its practicability.
Citation Count: Boutalis, Yiannis; Moor, Thomas; Schmidt, Klaus (2012). "Fuzzy Hybrid Systems modeling with application in decision making and control", IS'2012 - 2012 6th IEEE International Conference Intelligent Systems, Proceedings, pp. 290-296.
Fuzzy Hybrid Systems modeling with application in decision making and control
(2012) Boutalis, Yiannis; Moor, Thomas; Schmidt, Klaus
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.
Citation Count: Schmidt, Klaus; De Queiroz, Max H.; Cury, José E.R. (2010). "Hierarchical multitasking control of discrete event systems: Computation of projections and maximal permissiveness", IFAC Proceedings Volumes (IFAC-PapersOnline), Vol. 10, No. PART 1, pp. 98-103.
Hierarchical multitasking control of discrete event systems: Computation of projections and maximal permissiveness
(2010) Schmidt, Klaus; De Queiroz, Max H.; 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.
Citation Count: Boutalis, Yiannis; Schmidt, Klaus (2010). "Multi-objective decision making using fuzzy discrete event systems: A mobile robot example", 18th Mediterranean Conference on Control and Automation, MED'10 - Conference Proceedings, pp.575-580.
Multi-objective decision making using fuzzy discrete event systems: A mobile robot example
(2010) Boutalis, Yiannis; Schmidt, Klaus
In this paper, we propose an approach for the multi-objective control of sampled data systems that can be modeled as fuzzy discrete event systems (FDES). In our work, the choice of a "fuzzy" system representation is justified by the assumption of a controller realization that depends on various potentially imprecise sensor measurements. Our approach consists of three basic steps that are performed in each sampling instant. First, the current fuzzy state of the system is determined by a sensor evaluation. Second, the future fuzzy state is predicted for the possible control actions, and finally, a particular multi-objective weighting strategy allows to determine the control action to be applied. We demonstrate the features of our method by a mobile robot example. © 2010 IEEE.
Citation Count: Schmidt, E.G...et al. (2010). "Performance evaluation of FlexRay/CAN networks interconnected by a gateway", 2010 International Symposium on Industrial Embedded Systems, SIES 2010 - Conference Proceedings, 5th International Symposium on Industrial Embedded Systems, SIES 20107 July 2010through 9 July 2010, pp. 209-212.
Performance evaluation of FlexRay/CAN networks interconnected by a gateway
(2010) Schmidt, E.G.; Alkan, M.; Schmidt, Klaus; Yürüklü, E.; Karakaya, U.
The coexistence of both CAN and FlexRay networks in contemporary and future automobiles necessitates the use of FlexRay/CAN gateways that support the timely data exchange among the different networks. In this paper, we report on the implementation of such FlexRay/CAN gateway. Moreover, for the first time, we investigate appropriate network and gateway configurations that are beneficial for the overall network performance in the sense of small delays of gateway messages.