This paper presents the model–based diagnosis in the framework of discrete–event systems. Timed automata are used as a discrete–event representation which is suitable for consistency–based diagnosis. The diagnosti...
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This paper presents the model–based diagnosis in the framework of discrete–event systems. Timed automata are used as a discrete–event representation which is suitable for consistency–based diagnosis. The diagnostic statement is based on the observation whether the measured event–time sequences are consistent with the timed automata. The diagnostic algorithm can be applied online because it determines the fault occurrence recursively for the measured event–time sequences. The result is applied to diagnose valve faults in a chemical process.
The problem of robust fault detection in command inputs in the presence of modelling errors in linear time-invariant systems is addressed. The problem leads to a hypothesis test with a test statistic taking form of a ...
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The problem of robust fault detection in command inputs in the presence of modelling errors in linear time-invariant systems is addressed. The problem leads to a hypothesis test with a test statistic taking form of a weighted quadratic sum of independent normally distributed variables. It is rather difficult to compute the threshold for such a test and the corresponding error probabilities in an exact manner. Instead, the approximative results are derived by assuming assymptotic distribution of the test statistic towards normal distribution. Convergence conditions in case of growing number of summands are presented. Performance of the resulting detector is demonstrated on a simulated DC motor-generator rig.
Process manufacturing has some characteristics that makes it different from other types of industry. These specifics are reflected in the design of a process factory management system. This paper stresses some feature...
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Process manufacturing has some characteristics that makes it different from other types of industry. These specifics are reflected in the design of a process factory management system. This paper stresses some features of process manufacturing that have to be taken into account during the implementation of a production scheduling system.
Simulated Moving Bed (SMB) chromatographic separation processes show typical hybrid phenomena: discrete state jumps and switching dynamics. The SMB principle and two modelling approaches based on hybrid automaton are ...
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Simulated Moving Bed (SMB) chromatographic separation processes show typical hybrid phenomena: discrete state jumps and switching dynamics. The SMB principle and two modelling approaches based on hybrid automaton are presented and discussed within the context of hybrid systems theory. It is shown how these models are affected by open-loop and closed-loop control.
This paper presents the design of a reconfigurable LPV controller for the Boeing 747-100/200 longitudinal axis The control objectives are to obtain decoupled flight path angle and velocity command tracking during norm...
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This paper presents the design of a reconfigurable LPV controller for the Boeing 747-100/200 longitudinal axis The control objectives are to obtain decoupled flight path angle and velocity command tracking during normal operation and in the presence of an elevator failure. During normal operations, the controller uses the elevators and thrust for flight maneuvers. In case of elevator fault the control strategy uses th,e stabilizer as the alternative longitudinal control surface. Simulation results with elevator fault present show that the reconfigured controller stabilizes the faulty system.
The paper addresses a model based fault diagnosis for industrial actuators using a timed discrete-event representation. The consistency based diagnosis with timed automata as the timed discrete-event model is discusse...
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The paper addresses a model based fault diagnosis for industrial actuators using a timed discrete-event representation. The consistency based diagnosis with timed automata as the timed discrete-event model is discussed. An important aspect of this method is the use of the model to build a diagnostic system systematically. The only available information used for diagnosis is given by input and event sequences. The result shows that the temporal information included in the timed automata is beneficial for fault diagnosis of discrete-event systems.
The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of ...
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The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of the vehicles. (Letter type: Times New Roman, size: 10, line spacing: normal).
Different types of nonlinear controllers are designed and compared for a simple continuous bioreactor operating near optimal productivity. This operating point is located close to a fold bifurcation point. Nonlinear a...
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This paper attempts to look at the fundamental problem of fault detection and isolation (FDI) in nonlinear systems. Using the idea of input reconstruction by means of dynamic inversion the authors first discuss the pr...
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The nonlinear dynamic model of gas turbines is derived from first engineering principles, which consists of differential conservation balances completed by algebraic constitutive relations. This nonlinear dynamic mode...
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The nonlinear dynamic model of gas turbines is derived from first engineering principles, which consists of differential conservation balances completed by algebraic constitutive relations. This nonlinear dynamic model can then be transformed into input-affine form. The coordinate-functions of the state equation f(x) have very complicated algebraic structures, while the functions gi,(x) are constants. Because of this fact, the nonlinear dynamic analysis of the model, such as investigation of controllability and stability, can only be performed with difficulty or in some cases it can not be done. To solve this problem and to investigate the controllability and stability of the model in a more effective way the nonlinear dynamic model has to be transformed into LPV (Linear Parameter-Varying) model. This LPV-model can then be effectively used to develop some types of controllers to improve the dynamic response of the engine. In this paper we show the possible ways and steps of the transformation being neither obvious nor unique and the final form of the LPV-model of a pilot-plant gas turbine, which is installed in the Budapest University of Technology and Economics. Department of Aircraft and Ships on a test stand.
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