Real-time, in situ control of reactive ion etching is shown to reduce loading disturbance in an Applied 8300 reactive ion etch system. The etch process vehicle is CF4 etching of polysilicon. A real-time, multivariable...
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Real-time, in situ control of reactive ion etching is shown to reduce loading disturbance in an Applied 8300 reactive ion etch system. The etch process vehicle is CF4 etching of polysilicon. A real-time, multivariable feedback control strategy where key plasma parameters are fed back has been developed. This strategy is experimentally compared with standard industry practice and is shown to reduce the loading effect by 80%. This quantification of improvement is carried out in terms of a model from the literature which is reviewed and experimentally validated for the etch equipment and process used.
This paper presents a model-based approach to fault detection of dynamic systems, which is robust to unmodeled dynamics. A “Quasi-ARMAX model᾿ is first proposed for describing nonlinear systems by incorporating a gro...
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This paper presents a model-based approach to fault detection of dynamic systems, which is robust to unmodeled dynamics. A “Quasi-ARMAX model᾿ is first proposed for describing nonlinear systems by incorporating a group of certain nonlinear structures into a linear ARMAX structure. The model can be used for a best linear approximation of the system, as well as for the estimation of resulting unmodeled dynamics, by a hierarchical implementation of recursive identification. Then robust fault detection is performed based on thresholding approach using Kullback discrimination information as fault detection index, in which the estimated unmodeled dynamics is incorporated.
This research is concerned with fault detection of nonlinear systems using Kullback discrimination information (KDI) as an index. A hybrid quasi-ARMAX model is proposed, which combines a linear ARMAX model and a multi...
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This research is concerned with fault detection of nonlinear systems using Kullback discrimination information (KDI) as an index. A hybrid quasi-ARMAX model is proposed, which combines a linear ARMAX model and a multi-ARX-model based on interpolation. In the case where the faults occur on the ARMAX model part, a KDI-based "robust" fault detection is performed, in which multi-ARX-model part is treated as error due to nonlinear undermodeling. In other cases, the model is transformed into several local ARMAX models and fault detection is performed by using the KDI to discriminate each identified local model. In this paper, we mainly concentrate our discussion on the latter cases.
Proposes a combined controller structure and algorithm which integrates a cerebellar model articulation controller (CMAC) with fuzzy logic and bang-bang control under an intelligent supervisor. This neuro-fuzzy contro...
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Proposes a combined controller structure and algorithm which integrates a cerebellar model articulation controller (CMAC) with fuzzy logic and bang-bang control under an intelligent supervisor. This neuro-fuzzy controller has self-learning ability in real-time and can readily be applied to industrial process plants. The numerical results of simulation studies, which demonstrate the benefit and feasibility of the proposed algorithm, are presented.
This paper describes the approach to information sharing being adopted by Synapses, a pan-European project funded under the EU Health Telematics Programme. The emphasis in Synapses is on developing standards to enable...
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This paper describes the approach to information sharing being adopted by Synapses, a pan-European project funded under the EU Health Telematics Programme. The emphasis in Synapses is on developing standards to enable sharing, in whole or in part, of electronic healthcare records between distributed healthcare providers and institutions. The current technological solutions available for data sharing, including federated database systems, gateways, data warehousing, messaging and the web are insufficient on their own to meet the needs of Synapses. Thus in Synapses several different, but complementary technologies are merged in an open, distributed object-oriented environment. Furthermore, in order to safeguard the legal, ethical and clinical integrity of the record, it is essential not only to preserve the meaning of the data being transferred, but also its context and structure. Synapses solves this problem by defining a standard architecture for the federated electronic healthcare record.
Caltech's ducted fan experiment is used as a case study to investigate the properties of an algorithm for uniting local and global controllers proposed by Teel et al. (1997). To simplify the control design process...
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Caltech's ducted fan experiment is used as a case study to investigate the properties of an algorithm for uniting local and global controllers proposed by Teel et al. (1997). To simplify the control design process and to illustrate robustness, the ducted fan is modeled as a linear system with input rate limits. The local controller is an (fairly aggressive) LQR state feedback while the (semi-) global controller is a much less aggressive LQR state feedback. Closed-loop simulation results are provided using a fully nonlinear model of the ducted fan derived from wind tunnel data. Experimental results are also provided using the actual Caltech ducted fan.
The PARAGON toolset provides an environment for the modular and hierarchical design of resource-bound, real-time systems. It offers well-integrated graphical and textual specification languages with formal semantics. ...
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The PARAGON toolset provides an environment for the modular and hierarchical design of resource-bound, real-time systems. It offers well-integrated graphical and textual specification languages with formal semantics. Both languages are based on the Algebra of Communicating Shared Resources (ACSR), a process algebra with explicit notions of time, resources and priority. The integration of the three notions widens the applicability of the PARAGON formalisms to embedded systems, control systems, and fault-tolerant systems where run-time resource requirements must be considered during the design phase. To facilitate the design of complex systems, PARAGON allows a designer to describe a system incrementally through refinement steps that preserve system properties. To increase dependability of system models, PARAGON offers three types of analysis: automated verification of system requirements, interactive simulation, and testing. In this paper, we demonstrate the design methodology that PARAGON offers through examples.
The paper focuses on the speed control of stepping motors in a closed-loop configuration. An incremental optical encoder is used as the position transducer, allowing the achievement of a minor loop. The numerical cont...
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The paper focuses on the speed control of stepping motors in a closed-loop configuration. An incremental optical encoder is used as the position transducer, allowing the achievement of a minor loop. The numerical control algorithm is implemented using an IBM PC together with a specialized interface for stepper motors. The solution was obtained in two steps: the first was a nonlinear control law and the second was the improvement of the first one by using a PI part.
A new matrix rule-based model of discrete-part discrete event systems is given that, together with the well-known Petri net marking transition equation, yields a complete matrix-based dynamical description of these sy...
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A new matrix rule-based model of discrete-part discrete event systems is given that, together with the well-known Petri net marking transition equation, yields a complete matrix-based dynamical description of these systems. In this application to deadlock analysis, the exact relations between circular blockings and deadlocks are given for a large class of reentrant flow lines. Explicit matrix equations are given for online dynamic deadlock analysis in terms of circular blockings, and certain 'critical siphons' and 'critical subsystems'. This allows efficient dispatching with deadlock avoidance using a generalized kanban scheme. For the class of flow lines considered, the existence of matrix formulae shows that deadlock analysis is not NP-complete, but of polynomial complexity.
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.
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