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Complete Disagreement in Redundant Real-Time control Applications

IFAC Proceedings Volumes 1998年第4期31卷 223-228页

作者： G. Latif-shabgahi J.M. Bass S. Bennett Department of Automatic Control and System Engineering The University of Sheffield Mappin Street Sheffield S1 3JD UK

Redundant application algorithm “variants” are used to minimise errors in fault-tolerant real-time control systems. Voting algorithms arbitrate between variant results to select a single, hopefully correct, output. Both variants and voting algorithms can be implemented in either hardware or software. The behaviour of voting algorithms in multiple error scenarios is considered in this paper. Complete disagreement is defined as those cases where no two variant results are the same. A novel algorithm for real-time control applications, the smoothing voter, is introduced and its behaviour compared with previously published algorithms. Software implemented error-injection tests, reported here, show that the smoothing voter achieves a compromise between the result selection capabilities of the median voter and the safety features of the majority voter.

关键词： Fault-tolerance Embedded systems Redundancy Safety-Critical systems

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Behavioral model identification

Behavioral model identification

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IEEE Conference on Decision and control

作者： R. Johansson M. Verhaegen C.T. Chou A. Robertsson Department of Automatic Control Lund Institute of Technology Lund University Lund Sweden Department of Electrical Engineering System and Control Engineering Group TU Delft Delft Netherlands

This paper presents theory and algorithms for system identification suitable for the framework of behavioral system theory. An algorithm based on algebraic system theory and realization theory (Ho-Kalman realization) in a subspace model identification framework is presented. The novel approach considered consists of the formulation of input-output data as an impulse response model and the subsequent application of state-space realization. As a special case, behavioral model identification from finite data sequences is demonstrated.

关键词： Power system modeling system identification Context modeling Matrix decomposition control engineering Fitting Mathematical model Data analysis Linear systems Regression analysis

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Adaptivity in Human-Computer Interface systems: Identifying User Profiles for Personalised Support

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IFAC Proceedings Volumes 1998年第26期31卷 407-412页

作者： M. Dimitrova G. Johannsen H.A. Nour Eldin J. Zaprianov M. Hubert Institute of Control and System Research Bulgarian Academy of Sciences PB 79 1113 Sofia Bulgaria Laboratory for Systems Engineering and Human-Machine Systems (IMAT-MMS) University of Kassel D-34109 Kassel Germany Group of Automatic Control and Technical Cybernetics atk D-42097 Wuppertal Germany

Adaptivity for user "personalised" support is viewed as complementary to systems for cognitive support and is related to the following aspects of user modelling: individual user profile, user style/state diagnosis, context of work and mental workload prediction. The paper reports the results of an empirical study revealing a particular kind of contextual influences on user behaviour, namely, the freedom to choose the set of operations to be performed from a larger set of tasks, valid for all users at the basic skill level of performance. Stability of patterns was found on the level of minimal reaction times (RTs), but not on the level of mean RTs. Neural networks successfully generalised the minimal RT profiles across contexts.

关键词： User interfaces human-centered design mental workload interface adaptation monitoring neural networks

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A Rotating Sonar and a Differential Encoder Data Fusion for Map-Based Dynamic Localization

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IFAC Proceedings Volumes 1998年第3期31卷 183-187页

作者： Haeyong Yang Hakyoung Chung KyuCheol Park Jang Gyu Lee LG Industrial System Research & Development Center Anyang-shi Kyongki-do 430-080 Korea Department of Control and Instrumentation Engineering Seoul National Polytechnic University Seoul 139-743 Korea Automatic Control Research Center School of Electrical Engineering Seoul National University Seoul 151-742 Korea

In this paper, a dynamic localization method using a rotating sonar and a map is proposed. The proposed method is implemented by using an extended Kalman filter. The state equation is based on the encoder propagation model and the encoder error model, and the measurement equation is a map-based measurement equation using a rotating sonar sensor. By utilizing sonar beam characteristics, map-based measurements are updated while a mobile robot is moving continuously. Monte-Carlo simulation shows that the proposed global position estimator has the performance of a few millimeter order in position error and of a few tenth degrees in heading error.

关键词： Dynamic Position estimation Model-based recognition Ultra sonic transducer Kalman filter

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Genetic Algorithms for Scheduling Optimization on a Multi-Product Batch Processing Machine

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IFAC Proceedings Volumes 1997年第14期30卷 115-120页

作者： L. He N. Mort Department of Automatic Control and System Engineering University of Sheffield UK

This paper describes loading polices for the scheduling problem on a multi - product batching processing machine(BPM) which can process a batch of jobs simultaneously with a known and fixed number of jobs and their ready time. The different jobs are dispatched and sequenced in order to minimize the makespan and maximize the utilization of the servers. As an extension to the basic model of previous work (Fanti et al, 1997)) for BPM scheduling, we build up the model to schedule n jobs on m identical servers in which the optimization procedure results in a complex NP-hard combinatorial problem. Genetic Algorithms(GAs) are applied to solve this scheduling problem where we apply the features of elitist strategy GAs to develop a group of MATLAB functions for solving the BPM scheduling problem. This result is the optimal solution. This experiment demonstrates that GAs can provide a robust search procedure in the optimization of scheduling problem which has high dimensionality, multi-modality, discontinuity and noise (DeJong, 1975).

关键词： Optimization Scheduling Algorithms Batch-Processing Machine Genetic Algorithms

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Stability analysis of a kind of large-scale systems composed of symmetrically coupled subsystems

Stability analysis of a kind of large-scale systems composed...

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1997 American control Conference

作者： Gao, LQ Leng, KP Zhang, SY Department of Automatic Control Northeastern University Shenyang Liaoning China Open Laboratory of Complex System Engineering Institute of Automation Academia Sinica Shenyang Liaoning China

This paper discusses stability for a class of symmetric composite systems. For the asymptotical stability of the overall system without control a necessary and sufficient condition is given, It is shown that Lyapunov ... 详细信息

ISBN: (纸本)0780338332

关键词： large-scale systems asymptotic stability linear systems Lyapunov methods matrix algebra control system analysis large-scale systems symmetrically coupled subsystems asymptotic stability necessary condition sufficient condition Lyapunov function linear systems matrix algebra

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A mathematical approach to describing a class of hybrid systems

A mathematical approach to describing a class of hybrid syst...

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Workshop on Parallel and Distributed Real-Time systems

作者： R. Drath Department of Automatic Control and System Engineering Technical University Ilmenau Germany

Methods for describing continuous respectively discrete event systems have been thoroughly explored, but there is a need for universal methods to describe hybrid systems, in which continuous, as well as discrete subsystems are combined. Mathematical techniques are just emerging and have to be developed further. In this paper a new mathematical approach to modelling a class of hybrid systems is presented. A numerical example illustrates the principle.

关键词： Switches Discrete event systems Power system modeling Continuous time systems Petri nets Mathematical model Differential equations Sampled data systems Discrete time systems Boolean functions

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IEEE International Symposium on Intelligent control (ISIC)

作者： I. Eminoglu D.A. Linkens Department of Automatic Control and System Engineering University of Sheffield Sheffield UK

This paper investigates the effects of reducing the number of rules in a fuzzy logic controller (FLC) for a permanent magnet direct current (PMDC) motor. The reliability of the resulting controller, with fewer rules, is also investigated. First, rule extraction is shown front typical transient responses of a PMDC motor when the reference speed changes in a step-like manner. Next, the total number of rules is reduced from 49 rules to 9 rules by eliminating similar fuzzy rules; their corresponding membership functions are then replaced by other already available membership functions. Finally, the FLC consisting of 9 rules has been chosen in this study to investigate the sensitivity of the controller. The values in the decision table are changed in the range of /spl plusmn/30%. It is found that these variations in the rule decision table do not cause any instability problem in the proposed FLC.

关键词： Fuzzy logic control systems Motor drives DC motors Fuzzy systems Fuzzy control Choppers automatic control Permanent magnet motors Voltage

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Hydraulically coupled power-plants commitment within short-term operation planning in mixed hydro-thermal power systems

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EUROPEAN TRANSACTIONS ON ELECTRICAL POWER 1997年第5期7卷 323-330页

作者： Rakic, MV Markovic, ZM [?]Dr. Milan V. Rakic (1938) received his electrical engineering degree in 1962 his M.S. degree in 1972 and his Ph.D. degree in 1993 from the University of Belgrade Yugoslavia. He made additional studies in operations research and system science at Stanford University Department of Operations Research Stanford/California USA and Western Reserve University System Research Center. Cleveland/Ohio USA in 1969/1970. He joined the Mihajlo Pupin Institute Department of Automatic Control Belgrade/Yugoslavia in 1962. He was engaged in large-scale system control studies and research. Since 1975 he has been working on the development of methods and software for power system operation planning. He is currently a senior research associate at the Mihajlo Pupin Institute. (Mihajlo Pupin Institute Volgina 15 POBox 15 11050 Belgrade Yugoslavia Phone: +381-11-773-503 Fax: +381-11-773-835)

A new method for short-term operation planning and power exchange scheduling of interconnected hydrothermal power systems is proposed in the paper. The criterion function is the total variable profit obtained sales of energy to customers within the system, exchange of energy with other systems, diminished by the cost of system operation. The method is based on Lagrangian relaxation, decomposition technique and successive solution of dual and primal problems. The dual and primal problems are decomposed and solved using appropriate optimization methods, while Lagrangian multipliers are corrected using subgradient method. Dual hydro subproblems are solved using linearization and network flow method. Special modification of the algorithm is made so as to enable commitment of hydro power plants, taking into account bilogical constraints on minimal flow of water downstream of the hydro power plant. The efficiency of the method is illustrated on a test problem.

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An error analysis of GPS compass

An error analysis of GPS compass

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SICE Annual Conference

作者： Chansik Park Ilsun Kim Gyu-In Jee Jang Gyu Lee Application System Development Team Network Division Samsung Electronics Seoul South Korea Multimedia Laboratory. Corporate Technical Operations Samsung Electronics Company Limited Suwon South Korea Department of Electronics Engineering Konkuk University Seoul South Korea Automatic Control Research Center School of Electrical Engineering Seoul National University Seoul South Korea

ISBN: (纸本)0780342089

In this paper, analytical error characteristics of GPS compass which determines heading and elevation of the vehicle using carrier phase measurements from two antennas is given. The derived result gives clear analysis of error statistics on attitude determination using GPS carrier phase measurement. It shows the accuracy of measured attitude relies on satellite geometry, performance of receiver, baseline length, baseline configuration and nominal attitude of vehicle. It is also shown that to obtain more precise heading, longer baseline along the vehicle is preferred and the accuracy of heading is always better than that of elevation since the vertical measurement uncertainty caused by geometry of satellites affects only on that of elevation. These results can be applied to basic directions for attitude determination: to what direction should the baseline be located to minimize the error, which satellites should be selected to minimize the error. These must be important and useful pre-information in attitude determination problem. An application to real data shows that the predicted error by the proposed method coincides with that of experiments.

关键词： Error analysis Global Positioning system Vehicles Position measurement Satellites Phase measurement Geometry Antenna measurements Length measurement Measurement uncertainty

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