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10th IASTED International Conference on control and Applications, CA 2008

作者： Kashimura, Takashi Hori, Noriyuki Presently at Automobile RandD Centre Honda RandD Co. Ltd. 4630 Shimotakanezawa Haga-machi Haga-gun Tochigi 321-3393 Japan Digital Control Laboratory Graduate School of Systems and Information Engineering University of Tsukuba 1-1-1 Tennoudai Tsukuba Ibaraki 305-8573 Japan

ISBN: (纸本)9780889867468

A technique is proposed for incorporating an integrator in a digital control system that is redesigned using a Diophantine equation from an analog control system, which may or may not include an integrator. This is achieved by arranging an Eliminant matrix of the plant so that a certain constraint is imposed on the resulting control system without tampering its internal stability for non-pathological control rates. Experiments are carried out for roll-angle control of a miniature airborne mechanism, which require good disturbance rejection properties, to show that the proposed digital control system has good step-tracking and step-disturbance rejection performances even with a low control rate at which the widely used Tustin's control system yields unsatisfactory results.

关键词： Attitude control

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Chaotic behavior of new experimental data of the LTGP (2004-2006) confirm possible relation to seismic activity in Western Greece

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Journal of Physics: Conference Series 2008年第1期96卷 012159-012159页

作者： Giannakopoulos, K. Ifantis, A. Electronics Laboratory Department of Physics University of Patras Patras 26500 Greece Digital Systems and Media Computing Laboratory Faculty of Sciences and Technology Hellenic Open University Patras 26222 Greece Control Systems and Signals Laboratory Department of Electrical Engineering Technological Educational Institute of Patras Patras 26334 Greece Seismological Laboratory Department of Geology University of Patras Patras 26500 Greece

Observations of the long-term geoelectric potential (LTGP) difference are presented in this paper. The data have been collected during a three-year (2004-2006) investigating period. Moreover, this paper constitutes a continuation of two previously published works with eleven-year (1993-2003) experimental data. For data logging purposes, an automatic system for collection, transfer and processing of geoelectric measurements operates at the Seismological laboratory of the University of Patras. The analysis of these data using Lyapunov exponents and Takens estimator confirm their quite chaotic behavior. The Lyapunov exponents have also been calculated for short periods of twenty days, i.e. ten days before and ten days after the earthquakes occurred during this three-year period. By thorough examination of the resulting Lyapunov spectrums, it seems that these are subject to possible changes prior to an earthquake. © 2008 IOP Publishing Ltd.

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Exact Discrete-Time Models for Some Second-Order Nonlinear systems

Exact Discrete-Time Models for Some Second-Order Nonlinear S...

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SICE Annual Conference

作者： Yasuyuki Tomita Noriyuki Hori Digital Control Laboratory Graduate School of Systems and Information Engineering University of Tsukuba Tsukuba Japan

For a class of second-order nonlinear systems, this paper presents the exact discretization method based on the linearization of such nonlinear systems using suitable variable transformations. Unlike the existing method that is based on numerical integrations, such as the forward difference model, the derived discrete-time equation gives the values that match exactly those of the differential equation at the discrete-time instants for any discretization interval. Simulation results are presented to confirm the validity of this model

关键词： Nonlinear systems Riccati equations Nonlinear equations Linear systems Sampling methods digital control Differential equations Power system modeling systems engineering and theory Difference equations

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Approximate Discrete-Time Feedback Linearization of a Constant-Parameter Riccati System

Approximate Discrete-Time Feedback Linearization of a Consta...

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SICE Annual Conference

作者： Hidefumi Takahashi Noriyuki Hori Digital Control Laboratory Graduate School of Systems and Information Engineering University of Tsukuba Tsukuba Japan

An approximate, discrete-time, linearizing feedback law is presented for systems whose dynamics can be modeled by a Riccati differential equation with constant parameters. Although the original equation is affine, its exact (step-invariant) discrete-time model, which gives the exact value at the sampling instants for any sampling interval for piece-wise constant inputs, is not. Since this fact can make the control law synthesis intractable, approximations of the exact model into forms that are simpler for control input synthesis are proposed. In particular, the first- and second-order Pade approximations as well as the proposed approximations are considered. Simulation studies are carried out to show that the proposed method gives the best results among those considered in this study; i.e., the sampled-and-held method, those based on Pade approximations, and the proposed method

关键词： Linear approximation Feedback Riccati equations digital control control systems Sampling methods Nonlinear control systems Nonlinear systems Differential equations Linear systems

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Application of digital control theory to exact discretization of a logistic equation with a constant term

Application of digital control theory to exact discretizatio...

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IEEE Conference on control Technology and Applications (CCTA)

作者： N. Hori C.A. Rabbath Digital Control Laboratory Graduate School of Systems and Information Engineering University of Tsukuba Tsukuba Ibaraki Japan Defence Research and Development Canada Val-Belair QUE Canada

This paper presents an exact method of discretizing a logistic differential equation with a constant term (a class of Riccati equation), which are prevalent in a variety of fields, using a common knowledge in digital control theory. The resulting model gives the value that is exact at the discrete-time instants for any discretization period. Two existing methods that can lead to an exact discrete-time model are second-order and shown to be based on diverging variables, while the one proposed in this study is first-order and not prone to such a numerical problem. A simulation result is presented to illustrate this issue

关键词： digital control Logistics Riccati equations Nonlinear systems Differential equations Nonlinear equations Chaos Linear systems Nonlinear control systems Sampling methods

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Four-quadrant sensorless SRM drive with high accuracy at all speeds

Four-quadrant sensorless SRM drive with high accuracy at all...

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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： G. Suresh B. Fahimi K.M. Rahman M. Ehsani I. Panahi Power Electronics Laboratory Department of Electrical Engineering Texas A and M University College Station TX USA Digital Control Systems Texas Instruments Inc. Stafford TX USA

This paper describes a sensorless, four-quadrant switched reluctance motor (SRM) drive with high position resolution and accuracy at all operating speeds. In order to achieve sensorless control, a modified amplitude modulation scheme is used. Using this method, very high position resolution and accuracy comparable to that of a 14-bit resolver has been achieved. Detailed simulation of the drive system has been carried out using Matlab-Simulink in order to understand the dynamics of the system. For validation purposes, comprehensive set of experiments were performed on a 500 W, 100 V, 3000 RPM, 6/4, three-phase drive system and results are presented. The desired operations of a typical 4-quadrant drive, viz., motoring and generating in the forward and reverse directions have been achieved experimentally and the results are included. A brief analysis on the resolution, accuracy, speed range and transient stability of the sensorless method, which are very essential for practical design of any drive system is also presented. Some of the practical constraints in implementing the modulation scheme like the effect of high frequency signal injection on the sensitivity, effect of mutual coupling on the performance of the sensorless scheme are also discussed.

关键词： Reluctance motors Reluctance machines Sensorless control Amplitude modulation Computer languages Signal resolution Transient analysis Stability analysis Frequency Mutual coupling

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Self-tuning control of switched reluctance motors for optimized torque per ampere at all operating points

Self-tuning control of switched reluctance motors for optimi...

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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： B. Fahimi G. Suresh J.P. Johnson M. Ehsani M. Arefeen I. Panahi Department of Electrical Engineering Power Electronics Laboratory College Station TX USA Digital Control Systems Texas Instruments Inc. Stafford TX USA

Online self-tuning of control angles of a switched reluctance motor (SRM) is essential to optimize its performance in the presence of manufacturing imperfections. This paper reports an adaptive control scheme to optimize the torque per ampere at low and high speeds using artificial neural networks (ANN). An heuristic optimization technique has been introduced to find the changes in control angles. Using these results, the ANN will update its synaptic weights. Computer simulation has been employed to show the feasibility of this approach. Experimental results are provided to demonstrate the working of the self-tuning control.

关键词： Torque control Reluctance motors Reluctance machines Artificial neural networks Inductance IEEE members Adaptive control Manufacturing Computer simulation Programmable control

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THE CALLING(SM) NETWORK - A GLOBAL WIRELESS COMMUNICATION-SYSTEM

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 45-61页

作者： TUCK, EF PATTERSON, DP STUART, JR LAWRENCE, MH Calling Communications Corporation. 1900 West Garvey Ave South. Suite 200 West Covina CA 91790 USA. Chairman of Calling Communications Corporation. He is also the Managing Director of Kinship Venture Management Inc. the general partner of Kinship Partners 11 and a General Partner of Boundary the general partner of The Boundary Fund. As a venture capitalist he has founded or participated in founding several telecommunications companies including Calling Communications Corporation Magellan Systems Corporation manufactures of Global Positioning System receivers Applied Digital Access manufacturer of DS-3 test access and network performance monitoring equipment Endgate Technology Corporation specialists in satellite phased array antennas and Poynting Systems Corporation. now a division of Reliance Corporation manufacturers of fibre optic transport equipment. He was a founder of Kebby Microwave Corporation where he invented the first solid-state. frequency-modulated commercial microwave link system. The company was acquired by ITT Corporation where he rose to the position of V.P. and Technical Director of ITT North America Telecommunications Inc. Subsequently he was V.P. of Marketing and Engineering at American Telecommunications Inc. (ATC). He was founding Director of American Telecom Inc. a joint venture between ATC and Fujitsu and has served on more than 20 boards of directors including those of three public companies. He has authored articles on microwave engineering and telephone signalling and was a contributor to Reference Data For Radio Engineers. He is a graduate of the University of Missouri at Rolla where he was later awarded an honorary Professional degree and serves on its Academy of Electrical Engineering. Mr Tuck is a Senior Member of the IEEE a Fellow of the Institution of Engineers (Australia) a Professional Member of the AIAA and a registered professional engineer in three states. More than 25 years of experience in the telecommunications industry where he has been responsibl

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world's largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K(alpha)-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.

关键词： LOW EARTH ORBIT SATELLITE COMMUNICATIONS FAST PACKET SWITCHING EARTH FIXED CELLS ADAPTIVE ROUTEING LIGHT SPACECRAFT K(A) BAND PHASED-ARRAY ANTENNAS

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ACQUISITION REFORM AND BEST PRODUCT PROCUREMENT - AN engineering VIEW

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NAVAL ENGINEERS JOURNAL 1994年第6期106卷 41-57页

作者： FISHER, DA SKOLNICK, A He has been involved with several weapon system developments. Among these were the Trident II fire control and navigation systems the BSY-I Anti-Submarine Warfare System and the Navy standard computers (UYK44 and EMSP). He served as manager of the Digital Circuits Engineering Branch and was then appointed as manager of the Automatic Test Equipment (ATE) Technology Division. As manager of the ATE Technology Division he was responsible for the SP-23 Fire Control System Support Project the SP-24 Navigation Project and the Fleet Progressive Maintenance Program (2M/ATE). This Division was responsible for selection and application of electronic product technology and for developing fleet test and repair techniques. He holds a B.S. in Electrical Engineering from the University of Evansville and is currently pursuing a Masters of Public Administration at Indiana University-Purdue University Indianapolis. Dr. Alfred Skolnick:retired from the Navy in 1983 with the rank of captain. He is president of System Science Consultants (SSC) specializing in strategic planning technical program definition technology assessment and engineering analyses on selected matters of national interest. Dr. Skolnick taught mathematics and management sciences at University of Virginia and Marymount University. He is adjunct faculty at Northern Virginia Community College. From 1985 to 1989 he was president of the American Society of Naval Engineers. In the Navy he served at Applied Physics Laboratory/The Johns Hopkins University then aboard USSBoston(CAG-1) and played leading roles in several weapon system developments inertial navigation (Polaris) deep submergence (DSRV) and advanced ship designs (SES). He later was director Combat System Integration Naval Sea Systems Command and head Combat Projects Naval Ship Engineering Center. In 1975 he became a major project manager and led the Navy's High Energy Lasers Program in 1981 he was assigned all Navy Directed Energy Weapons development efforts. He was vice president advanced tech

The military services are being moved in the direction of performance-based specifications and standards. They are being steered against dictating ''how to'' produce an item since such action forecloses on the ability to gain access to components or technology that may have a commercial equivalent. Why should the engineering community embrace the new approach? Aside from the obvious weight of it being approved policy, therefore currently mandated, it warrants examination because it is the correct approach at this time when applied to appropriate products. Military specifications and standards are to be displaced then, by acceptable alternative contractor design solutions. Industry bidders will be allowed to propose the particular design details, permitting procurement flexibility by contractually citing only system level or interface requirements, both physical and functional. Hopefully, this can broaden the industrial base and increase competition with reduced costs to follow. Conceptually, the approach appears both performance-sensible and cost-attractive (there are, of course, consequent risks) but how does implementation proceed? Is it possible to pursue the goals envisioned along paths that are not in themselves experimental? Can the American postulate, minimal loss of life and limb to U.S. military people, continue to be honored? Experience and track record elsewhere imply encouraging possibilities in select situations-useful prospects are identified and discussed in practical terms.

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Discrete‐time model of an induction motor

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European Transactions on Electrical Power 1991年第2期1卷 65-71页

作者： Böcker, J. Joachim Bijcker (1957) is manager of the control engineering laboratory at the Institute of Drive Systems and Power Electronics of AEG in Berlin/ Ger-many. He studied electrical engineering at the Technical University of Berlin where he received the Dipl.-Ing. and Dr.-Ing. degrees in 1982 and 1988 respectively. From 1982 to 1987 he was a Research and Teaching Assistant at the 1st Institute of Mechanics Technical University of Berlin. Main research interests included nonlinear and passive systems. He has been with AEG since 1988. His current interests are associated with digital control of motors and inverters. (AEG AG Institute of Drive Systems and Power Electronics HollanderstraBe 3 1 - 34 W- lo00 Berlin 5 1 T +49 30145 01-3 22)

If a state‐space observer of a continuous‐time process is to be realized on a sampling microprocessor system, a discrete time model of the process is needed. Time‐varying continuous‐time parameters require the on‐line computation of the discrete‐time model. For this purpose numerical integration algorithms are used to get an approximate model instead of the exact model in discrete‐time. For the model of an induction motor it is pointed out that the often‐used first‐order algorithm of Euler (RK1) is crucial. Even the choice of the continuous‐time differential equation system, which has to be discretized, influences the quality of the discrete‐time approximation in a decisive manner. On the one hand even stability problems appear while on the other hand, by choosing the equation system in a skilful manner, one obtains a simple and accurate discrete‐time model, which can be used for microprocessor implementations. Copyright © 1991 John Wiley & Sons, Ltd.

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