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IEEE International Conference on Plasma Science (ICOPS)

作者： J.A. Vladimer V.R. Ewell M.C. Lee P.H. Doherty D.T. Decker D.N. Anderson J.A. Klobuchar Electrical Computer and Systems Engineering Department Boston University Boston MA USA Institute for Scientific Research Boston College Graduate School Newton MA USA Phillips Laboratory. Hanscom Air Force Base Ionospheric Effects Branch MA USA

Summary form only given. Variability of total electron content (TEC) in the equatorial anomaly region of the ionosphere can be studied extensively using the results of measurements taken by the NASA/CNES satellite, TOPEX/Poseidon, which provides global ocean coverage (0 to 360 degrees longitude, -66 to +66 degrees latitude). The NASA radar altimeter (NRA) is the first spaceborne dual-frequency altimeter capable of accurately measuring vertical ionospheric TEC below 1340 km. TOPEX TEC observations have already been used to support results from an ionospheric measurement campaign that was conducted in equatorial anomaly regions of South America by Phillips laboratory.in Spring, 1994. The best agreement in TEC values is seen during intervals of longitudinal proximity of the satellites' paths. Vertical measurements from TOPEX are obtained at a rate of one per second at 5.3 and 13.6 GHz. Along the same surface tracks every 10 days during which global ocean coverage is accomplished. TOPEX data records from 9/92 to 9/95 have been processed and reduced to one CDROM disc using one degree averaging over 110 km. Along track for evaluation of TEC measurements. Various plotting programs have been developed to represent the data for observation of TEC values and the occurrence of the equatorial anomaly. To facilitate further TEC studies, interface software has been prepared to provide easy access to specific dates, local times and longitudes with identification of anomaly formation and structure. The TOPEX over-ocean data can be used as a supplement to land based measurements in applications to ionospheric research at low and middle latitudes. This study focuses on comparisons between TOPEX vertical TEC data and GPS equivalent vertical TEC measurements taken near the East and West coastal regions of South America. Also the Phillips laboratory.Global Parameterized Ionospheric Model (PIM) is utilized in an effort to estimate slant to vertical conversion errors.

关键词： Satellites Sea measurements NASA Oceans Spaceborne radar South America Laboratories Radar tracking Electrons Ionosphere

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Some possible new applications of a partial-discharge (PD) model and its relation to PD-detection sensitivity

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EUROPEAN TRANSACTIONS ON electrical POWER 1996年第6期6卷 445-448页

作者： Danikas, MG Dr. Michael Danikas (1957) received the B. Sc. in Electrical and Electronic Engineering from the University of Newcastle-upon-Tynel England the M. Sc. from the same University and the Ph. D. from Queen Mary College University of Londod England in 1980. 1982 and 1985 respectively. He is presently Assistant mfessor at Democritus University of Thnce/Greece Department of Electrical and Computer Engineering. His research interests are mechanism of partial discharges composite insulating systems under high electrical and thermal stresses polymer outdoor insulation insulating materials at very low temperatures and breakdown mechanism in insulating liquids. (Democritus University of Thrace. Department of Ekctrical anti Computer Engineering Electric Energy Systems Laboratory. GR-67100 Xanthi/Greece T +30541/79979 Fax +30-541127954.

In this paper some possibilities of further applications of a known ''Streamer Partial-Discharge Model'' are proposed. These possibilities refer to the relation between the observed partial-discharge (PD) magnitude and the applied field to the insulation. Furthermore, the model is a useful tool to investigate the sensitivity of a PD detector and also to compare the sensitivities between various PD detectors.

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Development of transient stability controller system (TSC) based on on-line stability calculation

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electrical engineering IN JAPAN 1996年第4期117卷 61-79页

作者： Ota, H Inoue, T Ito, H Fukushima, N Omata, K Morita, K Kokai, Y Chubu Electric Power Co. Graduated in 1955 from the Department of Electrical Engineering of the Faculty of Engineering University of Tokyo and joined Chubu Electric Power Co. in the same year. He is engaged mainly in developing technology for construction planning as well as protection stabilization and automatic control of power systems. He is currently a Director and Vice President of the company. He received an OHM Technology Award in 1971 and an Achievement Award from the I.E.E. Japan in 1992. Graduated in 1962 from the Department of Electrical Engineering Shibaura Institute of Technology and joined Chubu Electric Power Co. in the same year. He is engaged in the development of technology for large-scale centralized control of power systems as well as the networking of control computers. He is currently a System Analysis Group Chief in the System Operation Division of the company. Graduated in 1985 from the Department of Electronics and Electrical Engineering of the Faculty of Engineering Tokyo Institute of Technology and joined Chubu Electric Power Co. in the same year. He is engaged mainly in the development of technology for power system protection and stabilization. He is currently working in the System Analysis Group of the System Operation Division of the company. Toshiba Corporation Graduated in 1967 from the Department of Electrical Engineering University of Tokyo and joined Toshiba Corporation in the same year and engaged in development of power system control systems in Japan and abroad. He is currently a Chief of System Technology in the Power System Technology Division of the company. He is a member of the Theses Subcommittee of the 1995 World Energy Conference. He is an Assistant Secretary of the Japanese Committee of CIGRE and a member of the Japanese Subcommittee of CIGRE SC35 and 39. He is a member of IEEE. Completed his Master's course at the Science and Engineering Research Division of the Graduate School Waseda University in 1980 and joined Toshiba Corporation in the same year. H

A new transient stability controller system (TSC) based on on-line transient stability calculation has been developed. The TSC system prevents the power system from wide-area blackout by shedding generators optimally when a serious fault occurs. This system consists of a central processing unit (TSC-P), and four local units for fault detection (TSC-C), and seventeen units for generator shedding(TSC-T). The TSC-P selects optimal generators to be shed for stabilization based on on-line transient stability calculation for contingencies at 500 kV lines and buses every five minutes. The results are transmitted to the TSC-Cs periodically. Should any fault occur, only one TSC-C will detect the fault occurrence and send control signals to the TSC-Ts which actually generate shedding signals. To realize the TSC system, essential are fast stability evaluation methods for a large number of contingencies and effective selection methods of optimal generators to be shed for stabilization. This paper presents total algorithms applied in the TSC-P, the results of algorithm verification tests using a prototype system combined with a large-scale analog simulator, and the characteristics of the actual system.

关键词： power system stabilization generation shedding on-line stability calculation screening parallel calculation

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Categorical color projection for robot road following

Categorical color projection for robot road following

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IEEE International Conference on robotics and automation (ICRA)

作者： Nan Zeng J.D. Crisman Robotics & Vision Systems Laboratory Department of Electrical and Computer Engineering Northeastern University Boston MA USA

This paper shows that categorical color developed in Yue Du (1994) is a good representation of color space for some robot vision tasks. The authors use SCARF as a test case to compare 'equivalent' RGB, categorical color, and intensity robot vision algorithms on a difficult robot road following task. SCARF uses a full three-dimensional representation of color space to formulate road and off-road colors. Performing categorical color or intensity projection, the authors can model the road and off-road colors as single dimensional probability density functions. This greatly reduces the time to process the color image. Moreover, the authors show that categorical color is a good representation in that it outperforms an equivalent intensity algorithm on the robot tasks. Categorical color, while it cannot outperform the original RGB algorithm, performs well enough to be used in this particular robot application. Its effectiveness is verified by many experiments on difficult road image sequences.

关键词： Roads Robot vision systems Orbital robotics Color Machine vision Mobile robots Image segmentation Layout Image edge detection Degradation

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Task planning and project management using Petri nets

Task planning and project management using Petri nets

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IEEE International Symposium on Assembly and Manufacturing (ISAM)

作者： Jongwook Kim A.A. Desrochers A.C. Sanderson Center for Advanced Technology in Automation and Robotics and Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

The demand for effective project management increases as the complexity and cost of a project grown. This paper introduces an interactive project management approach based on the Petri net to overcome the limitations of network diagrams. In the Petri net based approach, the project manager does fine tuning of the planning and scheduling with the resource constraints embedded in the plan representation. The Petri net controller maintains three plan representations. The reference, monitor and predictor Petri nets. These three nets are configured with the resource database to form a feedback loop such that the controller can monitor and control the project online. This structure is applicable to the control of more general discrete event dynamic systems as well as the project management problem. In case no admissible control action can be found, the manager turns to the rescheduling/replanning mode to generate a new plan and schedule.

关键词： Project management Petri nets Monitoring robotics and automation Costs Resource management Building materials Scheduling Visualization Roads

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Robot motion planning for sensor-based control with uncertainties

Robot motion planning for sensor-based control with uncertai...

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IEEE International Conference on robotics and automation (ICRA)

作者： L.A. Page A.C. Sanderson Center for Advanced Technology in Automation Robotics and Manufacturing Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

This paper describes a new representation for sensing and control uncertainties in sensor-based robot control, and presents motion planning algorithms that use this representation. The planning algorithms employ a robot's sensing capabilities as needed to accomplish a task, by activating sensors at points or intervals during motion. A sensor is represented by three quantities: a domain, which is the set of robot configurations at which a valid measurement can be taken; an absolute sensing uncertainty held, which describes the sensor's absolute (global) accuracy; and an incremental motion uncertainty, which describes the sensor's relative (pertaining to displacements) accuracy. Control uncertainty represents the ability of a controller to drive the measured error near zero. These descriptions of sensing and control capability determine the evolution of uncertainty in a sensor-based motion plan. Two complementary algorithms for motion planning with the new representation are presented. One is a backprojection algorithm which searches globally (in configuration space and the available sensors) for ways to achieve a particular subgoal. The other searches locally (in path space) to satisfy all the constraints in a planning problem. Examples of uncertainty evaluation and motion planning in two degrees of freedom are presented.

关键词： Robot motion Motion planning Motion control Uncertainty Robot sensing systems Robot control Sensor phenomena and characterization Displacement measurement Motion measurement Error correction

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Preisach modeling of piezoceramic and shape memory alloy hysteresis

Preisach modeling of piezoceramic and shape memory alloy hys...

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IEEE Conference on Control Technology and Applications (CCTA)

作者： D. Hughes J.T. Wen Control Laboratory for Mechanical Structures (CLaMS) Center for Advanced Technology in Automation Robotics & Manufacturing Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

Smart materials such as piezoceramics and shape memory alloys (SMAs) exhibit significant hysteresis and in order to estimate the effect on open and closed loop control a suitable model is needed. One promising candidate is the Preisach independent domain hysteresis model that is characterized by the congruent minor loop and wiping out properties. Comparable minor loop and decaying oscillation test data for a multi-sheet piezoceramic actuator (made of lead zirconate titanate) attached to a flexible beam are presented and are seen to be very consistent with the two Preisach model properties. The commanded parameter is the sheet transverse electric field while the measured parameter is an approximately colocated strain induced in the beam. Equivalent data for a Nitinol SMA wire muscle, attached to the same beam, are also presented. The input and output parameters are the SMA current and a beam strain respectfully. The minor loop and wiping out evidence is less strong than that of the piezoceramic case, but encouraging. In all experiments the quasi-steady state responses were generated in order to avoid exciting beam flexible modes which would complicate the analysis.

关键词： Piezoelectric materials Shape memory alloys Hysteresis Strain measurement Shape control Open loop systems Testing Actuators Titanium compounds Electric variables measurement

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Synthesized passive feedback control of sensor-rich smart structures-experimental results

Synthesized passive feedback control of sensor-rich smart st...

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IEEE Conference on Control Technology and Applications (CCTA)

作者： P. Akella J.T. Wen Control Laboratory for Mechanical Structures Department of Electrical Computer and Systems EngineeringCenter for Advanced Technology in Automation Robotics & Manufacturing Rensselaer Polytechnic Institute RPI Troy NY USA

Passivity based controllers are used in structural control due to their inherent robustness properties. These controllers require sensor/actuator collocation. In this paper, we consider the design of a "squaring down" matrix which renders a system passive by using a linear combination of all collocated and non-collocated sensor/actuator pairs. The design uses experimental transfer functions and does not require the knowledge of the system model. The problem of finding the squaring down matrix is cast as a solution to a set of linear matrix inequalities (LMIs) subject to some additional performance considerations. The design procedure of the squaring down matrix assumes that velocity information is available from the sensors which is not generally the case. We show that the squaring down matrix can be implemented without the use of such velocity information. We provide experimental results gathered from the single link flexible beam setup in the C/sub La/MS laboratory.at RPI to show that implementation of passive loops without velocity measurements provides very good results.

关键词： Feedback control Linear matrix inequalities Intelligent sensors Control system synthesis Robust control Sensor systems Hydraulic actuators Transfer functions Laboratories Economic indicators

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Systematic design of novel architectures for implementation of Radon Transform

Systematic design of novel architectures for implementation ...

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Midwest Symposium on Circuits and systems (MWSCAS)

作者： D. Soudris T. Chronopoulos N. Koussoulas T. Stouraitis Department of Electrical & Computer Engineering Democritus University of Thrace Xanthi Greece Lab of Automation and Robotics Department of Electrical Engineering University of Patras Achaia Greece VLSI Design Laboratory Department of Electrical Engineering & Computer Technology University of Patras Achaia Greece

A systematic methodology is introduced for designing highly pipelined array architectures for implementation of Discrete Radon Transform and its Inverse, starting from the algorithmic level and ending with the architectural (hardware) level. Due to large amount of data, the original algorithm is partitioned into nested loops that can be easily mapped onto fixed-size hardware. The proposed methodology derives a plethora of alternative architectures, which meet various parameters such as high-throughput rate, maximum hardware utilization, and pipelinability. Moreover, the derived architectures are piecewise regular and consist of linear and/or 2-D systolic arrays.

关键词： Discrete transforms computer architecture Algorithm design and analysis Partitioning algorithms Hardware Systolic arrays Geophysics computing Concurrent computing Image reconstruction robotics and automation

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Attitude control without angular velocity measurement: a passivity approach

Attitude control without angular velocity measurement: a pas...

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IEEE International Conference on robotics and automation (ICRA)

作者： F. Lizarralde J.T. Wen Department of Electrical Engineering COPPE UFRJ Rio de Janeiro Brazil Center for Advanced Technology in Automation and Robotics Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

It is well known that the linear feedback of the quarternion of the attitude error and angular velocity globally stabilizes the attitude of a rigid body. In this note, we show that the angular velocity feedback can be replaced by a nonlinear filter of the quarternion, thus removing the need of direct angular velocity measurement. In contrast to other approaches, this design exploits the inherent passivity of the system; a dynamic observer reconstructing the velocity is not needed. An application of the proposed scheme is illustrated for the robot control problem. Simulation results are included to illustrate the theoretical results.

关键词： Angular velocity Velocity measurement PD control Feedback Quaternions Robot control Orbital robotics robotics and automation Space vehicles Proportional control

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