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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： I.N.M. Papadakis J.G. Reisman S.C.A. Thomopoulos Dept. of Electr. & Comput. Eng. Pennsylvania State Univ. University Park PA USA Decision and Control Systems Laboratory Department of Electrical and Computer Engineering Pennsylvania State University University Park PA USA

An effective method for visual pattern recognition using morphological techniques is presented. It is shown that it can be successfully used for the recognition of deformed letters. The method extracts morphological information by the successive dilation of an idealized letter set. At each stage a properly defined similarity index is computed. The maximum values of the similarity index for each stored letter are compared and are used for the classification decision. Classification results are presented for a set of deformed capital English letters with a realistic level of deformation. Skeletonization of the deformed pattern is shown to improve the performance of the classification method. The described method can be easily implemented using a parallel architecture.< >

关键词： Pattern recognition Artificial neural networks Feature extraction Clocks control systems Laboratories Data mining Parallel architectures Character recognition Tiles

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Harmonic insertion in PWM inverter drive schemes

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European Transactions on Electrical Power 1992年第3期2卷 143-151页

作者： Theocharis, J. Petridis, V. Dr.-Ing. John Theocharis (1956) graduated as an Electrical Engineer from Aristotelian University of Thessaloniki.Greece in 1980. From 1980 to 1985 he has been with the scientific staff of the Department of Electrical Engineering at the Aristotelian University where he received the Ph.D. degree in 1985. Since 1986 he is working as a lecturer and in 1990 he became assistant professor at the Department of Electronics and Computer Engineering in the m e university. His research activities include control power electronics and electrical motor drives. Recently he is working with the Neural Network Systems with applications to field oriented control problems. Aristotelian University of Thessaloniki School of Engineering Faculty of Electrical Engineering Dept. of Electronics & Computer Engineering P.O. Box 438 GR-Thessalonikil/Greece.T+3131/219784Fax + 3031/274868) Prof. Dr.-Ing. Vasilis Petridis (1946) graduated from National Technical University of Athens Greece in 1969.He obtained the M.Sc. and the Ph.D. in electronics and systems from the University of London in 1970 and 1974. respectively. H i s interests include applied automatic control neural networks drives dynamic systems robotics etc. He is currently professor in the Department of Electronics and Computer Engineering of the University of Thessaloniki. (Aristotelian University of Thessaloniki. School of EngineeringFaculty of Electrical Engineering Dept. of Electronics & Computer Engineering P.O. Box 438. GR-ThessaloniW Greece T+3031/219784.Fax+3031/274868)

The procedure of harmonic insertion is generalized in this paper. Analytical expressions of the voltage spectra are derived. The insertion of the 3rd harmonic to the modulating signal, which is of particular interest, is considered as a special case. It is demonstrated in this case that the fundamental harmonic component of the phase and the line‐to‐line voltage is not affected by the insertion of the 3rd harmonic for sufficiently high values of the chopping ratio. However it has been shown that the higher harmonic spectrum is significantly improved as compared to the case of pure sinusoidal modulation. For different values of the fundamental component the optimal values of the amplitude of the third harmonic to be inserted have been calculated so that the distortion factor of the higher harmonic spectrum is minimized. Other cases of harmonic insertion are also considered which provide spectrum efficiency improvement. Experimental results are given which have been obtained by means of a microcomputer controlled PWM generator constructed for this purpose. Copyright © 1992 John Wiley & Sons, Ltd.

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IMPROVING THE SHIP DESIGN, ACQUISITION AND CONSTRUCTION PROCESS

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NAVAL ENGINEERS JOURNAL 1992年第2期104卷 39-57页

作者： RYAN, JC JONS, OP J. Christopher Ryan:earned his bachelor's and master's degrees in Naval Architecture from Webb Institute and MIT respectively. He spent three years at the Advanced Marine Technology Division of Litton Industries working on the DD-963 class ship design and related computer aided design projects. he subsequently went to the Navy Department concentrating on early stage design of surface combatants for 12 years including work on the FFG-7 Sea Control Ship CSGN and CVV aircraft carrier projects. He then shifted focus and became the technical director for the Computer Supported Design Program in NavSea for five years. Mr. Ryan has served in several supervisory positions within the Ship Design Group in NavSea since that time. He is currently the project manager for the Ship Design Acquisition and Construction Process Improvement Project. Otto P. Jons:received a Diplom Ing. in shipbuilding from the Technical University of Hannover W. Germany and an M.S. in naval architecture and marine engineering from the Massachusetts Institute of Technology in 1967. He then joined Litton Ship Systems where he was responsible for the preliminary design of the DD-963 hull structure and then for ship systems as manager LHA Ship Systems Engineering Department. From 1972 to 1974 he was principal research scientist at Hydronautics. In 1976 as technical director he helped establish the local office of Designers and Planners. Otto Jons was one of the co-founders of Advanced Marine Enterprises Inc. in 1976 where he is corporate vice president engineering.

In the spring of 1990, the NavSea Chief Engineer initiated a project to improve the design, acquisition and construction (DAC) of U.S. Navy ships. The project's objectives are to reduce the time and cost of acquiring and operating Navy ships while improving their quality, unlike previous studies on the subject, the project utilizes a rigorous process analysis approach and attempts to use quantitative measures as the basis for recommending improvements. The paper is, of necessity, a status report on the progress of this project. Topics covered include: the DAC process;a look at the current state of ship acquisition time, cost, and quality;the methodology for process improvements;and early findings.

关键词： Naval Vessels

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PATH PLANNING FOR MOBILE MANIPULATORS FOR MULTIPLE TASK EXECUTION

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IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION 1991年第3期7卷 403-408页

作者： CARRIKER, WF KHOSLA, PK KROGH, BH Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

We consider the planning problem for a mobile manipulator system that must perform a sequence of tasks defined by position, orientation, force, and moment vectors at the end-effector. Each task can be performed in multiple configurations due to the redundancy introduced by mobility. We formulate the planning problem as an optimization problem in which the decision variables for mobility (base position) are separated from the manipulator joint angles in the cost function. The resulting numerical problem is nonlinear with nonconvex, unconnected feasible regions in the decision space. Simulated annealing is proposed as a general solution method for obtaining near-optimal results. The problem formulation and numerical solution by simulated annealing are illustrated for a manipulator system with three degrees of freedom mounted on a base with two degrees of freedom. These results are compared with results obtained by conventional nonlinear programming techniques customized for the particular example system.

关键词： Path planning Simulated annealing Cost function Numerical simulation Space stations Robotics and automation Manipulators Trajectory Constraint optimization Ear

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SYNTHESIS OF FEEDBACK-control LOGIC FOR DISCRETE MANUFACTURING systems

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AUTOMATICA 1991年第4期27卷 641-651页

作者： KROGH, BH HOLLOWAY, LE Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 United States

This paper concerns the supervisory coordination and control of concurrent activity cycles in automated manufacturing facilities. In contrast to commonly used simulation models which integrate the control policy with the system model, the state transition logic for the manufacturing equipment is represented by a class of controlled Petri nets (CtlPN) with external inputs to be determined by the control synthesis algorithm. We formulate the forbidden state control problem in the CtlPN context and present an algorithm for generating maximally permissive controls which guarantee the system will avoid the forbidden states while permitting a maximal amount of flexibility in the system operation. The problem formulation and control synthesis algorithm is illustrated for an example of AGV co-ordination, and several classes of manufacturing control problems which can be addressed within this framework are identified.

关键词： computer control control SYSTEM SYNTHESIS DISCRETE systems MANUFACTURING PROCESSES SUPERVISORY control SYNTHESIS METHODS

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A CERTAINTY EQUIVALENCE PRINCIPLE BASED NONLINEAR SEPARATION control RULE FOR RANDOM-ACCESS CHANNELS - STABILITY AND DELAY ANALYSIS

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INFORMATION SCIENCES 1991年第1-3期56卷 75-111页

作者： THOMOPOULOS, SCA Decision and Control Systems Laboratory Department of Electrical and Computer Engineering The Pennsylvania State University University Park Pennsylvania 1680 USA

Application of the certainty equivalence principle in the dynamic control problem of an unstable random access (RA) channel results in a nonlinear separation control rule which can be implemented in a decentralized fashion and yields maximum stable throughout e-1. Stability of the controlled RA channel is proven by showing that the channel backlog and its least squares estimate from an ergodic double Markov chain. Tight upper and lower bounds on the invariant probability distribution are also derived when the backlog is precisely known. The bounds are loglinear functions of the channel backlog and can be readily used to compute bounds on the average backlog and delay in the RA channel. An adaptive realization of the control is introduced for an RA channel with unknown traffic rates. Extensive simulation results are provided and the performance of our control is compared with other existing distributed controls.

关键词： Data Transmission

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IMPROVEMENT OF systems RELIABILITY USING ROBUST-control THEORY

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INTERNATIONAL JOURNAL OF systems SCIENCE 1991年第3期22卷 587-593页

作者： JAWORSKA, I TZAFESTAS, S Intelligent Robotic and Control Systems Unit Computer Engineering Department National Technical University of Athens Zografou 15773 Greece Warsaw University of Technology Warsaw Poland

In recent years reliable methods for designing multivariable feedback control systems have been intensively studied. System problems such as sensitivity, minimalization, robustnes to model uncertainties and systems fault tolerance have been the subject of particular investigations aiming to improve MIMO systems reliability. The purpose of this paper is to present some recent results in the area of linear multivariable control systems reliability improvement, which have been obtained using robustness theory. The research reported here is less than ten years old and is in continuous progress.

关键词： systems Science and Cybernetics

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Model Reference Adaptive control of a Gantry Crane Scale Model

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IEEE control systems 1991年第1期11卷 57-62页

作者： Butler, Hans Honderd, Ger Van Amerongen, Job Control Laboratory of the Department of Electrical Engineering Delft University of Technology 2600 GA Delft Netherlands Control Systems and Computer Engineering Laboratory Department of Electrical Engineering University of Twente 7500 AE Enschede Netherlands

A method of reference model decomposition, an extension of model reference adaptive control, is presented. The decomposition method can be regarded as a way of including knowledge about the structure and parameters of unmodeled dynamics in the adaptive system, making it possible to choose a lower order controller which is only equipped for the nominal process part. To illustrate the decomposition method, an adaptive controller for a scale model of a gantry crane is presented. Simplifying and linearizing the mathematical equations describing the crane yields a fourth-order model, of which the dynamics of the load swing take two. A standard adaptive control algorithm needs eight parameters, which in practice yields unacceptable behavior. The decomposition method allows the use of only two adjustable parameters, and real-time experiments showing practical results obtained with the method are described.< >

关键词： Adaptive control Cranes Programmable control Equations Mathematical model Laboratories Adaptive systems control systems Flexible structures Industrial control

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Model Quality and Optimal Identification for control

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IFAC Proceedings Volumes 1991年第3期24卷 817-822页

作者： P. Löhnberg B. Franke Control Laboratory Control Systems and Computer Engineering Group Department of Electrical Engineering University of Twente Enschede The Netherlands

Optimal parameter estimation and experiment design requires a weighting between the cost of parameter errors and that of identification itself. Having identified this need, the general principle to obtain both costs for using the model in control design is described. Fast experiment design is achieved by using analytic expressions to calculate the optimal experiment parameters. This is illustrated by a simple example. It is shown that the use of the resulting model criterion in optimal identification is equivalent to cautious stochastic control. A more realistic example is illustrated by simulation.

关键词： Bayes methods least squares approximation optimal control optimization parameter estimation random processes

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Monitoring Behavioral Evolution for On-Line Fault Detection

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IFAC Proceedings Volumes 1991年第6期24卷 313-319页

作者： L.E. Holloway B.H. Krogh Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 USA

The evolution graph monitor is defined and illustrated for on-line monitoring of computer-controlled processes with both discrete and continuous dynamics. Using a behavioral model specification of the process dynamics, the evolution graph monitor builds and maintain an efficient representation of the set of admissible system trajectories which are consistent with the on-line observations as they are received. In contrast to simulation-based methods, the evolution graph approach handles delayed, uncertain, and infrequent observations for systems with widely varying operating characteristics. A behavioral model specification and evolution graph monitor have been developed to perform on-line fault detection for an electric arc furnace in a continuous-caster steel mill. This application is used throughout the paper to illustrate the details of the approach.

关键词： Monitoring Failure Detection Discrete systems Casting Manufacturing Processes

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