A grey box model-based method for fault diagnosis is proposed in this paper which is based on a first principle model of the process unit: a heat exchanger, and on a grey box model of the fault: the deterioration of t...
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A grey box model-based method for fault diagnosis is proposed in this paper which is based on a first principle model of the process unit: a heat exchanger, and on a grey box model of the fault: the deterioration of the heat transfer surface by aging. Under normal operating conditions the heat transfer coefficient is constant or slowly decreasing due to a layer of settled material building up on the heat transfer surface, and we propose to use a recursive least squares estimator with forgetting factor to track the heat transfer coefficients during these stages. In old heat exchangers, big chunks of the settled material can break away from the surface causing the heat transfer coefficients to rise sharply. This fault is detected via detection of abrupt positive jump in the estimated heat transfer coefficients using a Hinkley detector
作者：
Milanovic, JV[?]Jovica V. Milanovic (1967) received the Dipl.-Ing. (Elec.) and M.Sc. (Elec. Eng.) degrees from the University of Belgrade. Yugoslavia. in 1987 and I99 I
respectively. One year he worked with “Energoproject-MDD”- Engineering and Contracting Co. in Belgrade as an engineer in designing power plants and substations. In late 1988 hejoined the Faculty of Electrical Engineering of the University of Belgrade first as an associate teaching assistant and then (since late 199 I) as teaching assistant at the Dept. of Power Converters and Drives. Between March 1993 and January 1996 he completed his Ph.D. at the University of Newcastle. Australia. at the Dept. of Electrical and Computer Engineering. Since February 1996 he is lecturer at the Department of Electrical Engineering and Computer Science at the University of Tasmania Austnlia. His major interests include synchronous machines and power system transients control and stability. (The University of Tasmania. Dept. of Electrical Engineering and Computer Science GPO Box 252-65 Hobart Tas 7001 Australia.Te1+61 362/262-753 Fax+61 369/262 136. e-mail: Jovica.Milanovic@eecs.utas.edu.au)
The paper presents the overview of load modelling for power-system damping and stability studies with main conclusions summarized from previous research. The attempt has been made to present a cross-section of the mos...
The paper presents the overview of load modelling for power-system damping and stability studies with main conclusions summarized from previous research. The attempt has been made to present a cross-section of the most exploited existing load models together with the most important conclusions drawn from their implementation in power-system stability programs. The current trends and latest results in the domain of damping of electromechanical oscillations in power systems are also presented. The effects of load dynamics on damping of electromechanical oscillations were analyzed on the basis of one of generic load models proposed in the past. The recent results further encourage investigation in this area and highlights the importance of proper load modelling.
A novel type of electro-optic diffractive element is presented which can satisfy the requirements for a high space-time bandwidth deflector while providing for two-dimensional random access beam steering control. The ...
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ISBN:
(纸本)0819425532
A novel type of electro-optic diffractive element is presented which can satisfy the requirements for a high space-time bandwidth deflector while providing for two-dimensional random access beam steering control. The basic device consists of a multichannel array of phase modulators fabricated using Lanthanum-modified Lead Zirconate Titanate (PLZT) operating as a programmable diffractive optical element. Two-dimensional deflection control can be readily obtained by crossing two one-dimensional arrays. This device is useful for wavelengths in the Visible to Mid-IR range and is based on PLZT ceramic materials which can be readily mass-produced. It possesses the versatility and multifunctionality of liquid crystal based optical phased array systems while allowing for very fast switching speeds with good thermal stability. We present a brief comparison of this novel deflector with other scanning technologies and outline the benefits and trade-offs of the PLZT-based device. Experiments on 16- and 32-channel arrays with fullwave voltages less than 400 volts demonstrate continuous lateral beam steering control of a HeNe laser beam. We also demonstrate full deflection control with a minimum number of control lines using a modified deflector arrangement. And we present measurements showing sub-microsecond switching speeds from such PLZT-based phase modulators. Mature versions of this type of scanner will find use in a wide variety of applications including 2-D and 3-D laser displays, laser communications, and LIDAR systems.
Interlaced systems constitute a class of systems only characterized by the zero entries of their matrix configuration and a local stabilizability condition. All these systems are globally stabilizable by a recursive d...
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ISBN:
(纸本)9783952426906
Interlaced systems constitute a class of systems only characterized by the zero entries of their matrix configuration and a local stabilizability condition. All these systems are globally stabilizable by a recursive design procedure which combines steps of backstepping and forwarding. When a nonlinear system misses this structural characterization, other types of conditions (sign, growth) are needed to ensure global stabilization.
This paper deals with the fault-tolerant control problem under nonlinear boiler systems with noise and disturbance. MCMBPC (Multivariable Constrained Model-Based Predictive controller) proposed by Wilkinson et al . is...
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This paper deals with the fault-tolerant control problem under nonlinear boiler systems with noise and disturbance. MCMBPC (Multivariable Constrained Model-Based Predictive controller) proposed by Wilkinson et al . is used and modified in this paper in order to be applied to nonlinear boiler systems. Fault-tolerant control scheme combining MCMBPC with a fault detection method based on the unknown input observer is proposed. The fault-tolerant controller proposed is shown, via simulation, to have acceptable tracking performance even under some faults of input valves in the boiler system.
Hybrid control systems are a combination of real-time control law and discrete-state logic. This paper describes how a Development Framework for control systems software has been adapted so that it may also handle dis...
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Hybrid control systems are a combination of real-time control law and discrete-state logic. This paper describes how a Development Framework for control systems software has been adapted so that it may also handle discrete events such as mode switching. The Framework provides a highly automated path from a controlengineering specification to a distributed system implementation. Simulink, an extension to Matlab, is used to specify control laws, and a statecharts tool, Statemate, is used to specify and model discrete-state components. The design phase of the Development Framework supports the integration of the two sets of specification. An inverted pendulum control system is introduced as a simple example of a hybrid system implemented using the Framework. The translation of statecharts to dataflow notations is described for the example system. General translation rules are also presented.
Formal verification of safety and timing properties of engineering systems is only meaningful if based on models which are systematically derived. In this paper we report on our experience using switched bond graphs f...
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A method of computing a reference input to achieve a desired finite output trajectory is presented. The technique is equally applicable to minimum, non-minimum phase, stable, and unstable systems. The approach is base...
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A method of computing a reference input to achieve a desired finite output trajectory is presented. The technique is equally applicable to minimum, non-minimum phase, stable, and unstable systems. The approach is based on the singular value decomposition (SVD) of the system's input-output matrix. A SISO formulation is introduced which forms the basis for an extension to MIMO systems.
In analyzing the behavior of refinery heaters, it turns out that the process dynamics is slow and can be cast into the form of input-output discrete-time controlled autoregressive and integrated moving-average (CARIMA...
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In analyzing the behavior of refinery heaters, it turns out that the process dynamics is slow and can be cast into the form of input-output discrete-time controlled autoregressive and integrated moving-average (CARIMA) model with large time-lag which poses difficulties in control design. To overcome these difficulties, modified Diophantine equations are introduced in this paper to facilitate the development of filtered outlet temperature predictions so that the closed-loop system (the refinery heater model with a recursive predictive controller) have desired stability properties. Simulation studies on a pilot-scale process heaters have illustrated the flexibility and computational effectiveness of the developed predictive control algorithm.
For nonlinear systems in extended strict feedback form, where unmeasured states enter linearly, we construct dynamic partial state feedback controllers that achieve the global asymptotic tracking of given reference tr...
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For nonlinear systems in extended strict feedback form, where unmeasured states enter linearly, we construct dynamic partial state feedback controllers that achieve the global asymptotic tracking of given reference trajectories while maintaining internal boundedness.
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