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IEEE Power and Energy Society General Meeting

作者： Jing Ma Tong Wang Zengping Wang Jie Wu James S. Thorp School of Electrical and Electronic Engineering North China Electric Power University and also with the Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University State Nuclear Electric Power Planning Design and Research Institute Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University

ISBN: (纸本)9781457710001

This paper develops a systematic procedure of designing global power system stabilizers (GPSSs) based on collocated control to enhance the damping during interarea oscillations. The availability of remote signals from phasor measurement units (PMUs) enables the wide-area control in large scale systems. The closed loop eigenvalues are excluded from a region of the complex plane by the collocated control algorithm guaranteeing that low frequency modes must be damped. The optimum locations for GPSSs were selected using controllability. The damping performance of a 16-machine, 68-bus study system reinforced with GPSSs is examined in the frequency and time domains. The simulation results show that the control scheme is able to damp out interarea oscillations following possible disturbances.

关键词： PMUs Interarea oscillations Collocated control Global power system stabilizers Phasor measurement units absorption of shock dinitrophenyl-aminopropyl-methylamine Oscillations control technology Complex Plane Power system stability computer algorithms

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Frequency Domain Time-Space Decomposition for Efficient Near Field Pressure Computations

Frequency Domain Time-Space Decomposition for Efficient Near...

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2011 IEEE Ultrasonics Symposium (IUS 2011)

作者： E.J. Alles K.W.A. van Dongen R.J. McGough Biomedical Ultrasound Engineering Laboratory Department of Electrical and Computer and Engineering Michigan State University East Lansing MI 48824-1226 Laboratory of Acoustical Imaging and Sound Control Faculty of Applied Sciences Delft University of Technology Delft the Netherlands

ISBN: (纸本)9781457712531

Time-Space Decomposition is one of the most efficient transient near-field pressure simulation schemes available for piston transducers, but suffers from two drawbacks. Every signal has to be individually programmed, and not all signals can be rewritten into the desired decomposition. In this work, an extension of the above method is presented in which the excitation signal is first transformed into the frequency domain and each of the frequency components is used as separate excitation signal. Spectral clipping is applied to reduce the number of terms and hence the computation time. By removing energy from the problem, the efficiency increases at the cost of accuracy. The achieved accuracy in the transient pressure field is known a priori and thus can be set prior to the actual simulation. Pressure fields obtained with the proposed method are compared to those obtained with Field II and with reference solutions obtained with an impulse response method. The proposed method reaches relative errors in the transient pressure field as low as 10~(-6) and is significantly more accurate than Field II which has difficulties reaching errors below 10~(-3). The time to reach an error of 10~(-2) using the proposed method is more than 100 × shorter than the time required by Field II to reach that same error.

关键词： Acoustics

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Improved servomechanism control design - Dynamically damped case

Improved servomechanism control design - Dynamically damped ...

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International Conference on control and Automation (ICCA)

作者： Aurélio T. Salton Zhiyong Chen Minyue Fu School of Electrical Engineering and Computer Science University of Newcastle Callaghan NSW Australia State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology China Department of Control Science and Engineering Zhejiang University China

Time optimal control (TOC) for servomechanism is not a practical controller due to the chattering phenomenon that occurs on the presence of noise and model uncertainty. Maybe the most popular attempt to transform this controller in a practical one comes from the so called Proximate Time Optimal Servomechanism (PTOS). This approach starts with a near time optimal controller and then switches to a linear controller when the system output approaches the target. While the chattering phenomenon is avoided, this comes at an expense in performance generated by the so called “acceleration discount factor”. This paper will present a controller that makes use of dynamic damping in order to push the acceleration discount factor arbitrarily close to one, thus practically eliminating the conservatism present in the PTOS. Experimental results support the proposed design.

关键词： Damping Servomechanisms Trajectory Acceleration control design Friction

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On Quaternion-Based Attitude control and the Unwinding Phenomenon

On Quaternion-Based Attitude Control and the Unwinding Pheno...

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American control Conference

作者： Christopher G. Mayhew Ricardo G. Sanfelice Andrew R. Teel Robert Bosch Research and Technology Center 4005 Miranda Ave. Palo Alto CA 94304 Department of Aerospace and Mechanical Engineering University of Arizona Tucson AZ 85721 Center for Control Engineering and Computation Electrical and Computer Engineering Department University of California Santa Barbara CA 93106-9560

ISBN: (纸本)9781457700811;9781457700804

The unit quaternion is a pervasive representation of rigid-body attitude used for the design and analysis of feedback control laws. Often, quaternion-based feedbacks require an additional mechanism that lifts a continuous attitude path to the unit quaternion space. When this mechanism is memoryless, it has a limited domain where it remains injective and leads to discontinuities when used globally. To remedy this limitation, we propose a hybrid-dynamic algorithm for lifting a continuous attitude path to the unit quaternion space. We show that this hybrid-dynamic mechanism allows us to directly translate quaternion-based controllers and their asymptotic stability properties (obtained in the unit-quaternion space) to the actual rigid-body-attitude space. We also show that when quaternion-based controllers are not designed to account for the double covering of the rigid-body-attitude space by a unit-quaternion parameterization, they can give rise to the unwinding phenomenon, which we characterize in terms of the projection of asymptotically stable sets.

关键词： attitude control Unwinding Quaternion lifts attitude in space Injective Human Posture controllers Attitude

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Universal squash model for optical communications using linear optics and threshold detectors

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Physical Review A 2011年第2期84卷 020303(R)-020303(R)页

作者： Chi-Hang Fred Fung H. F. Chau Hoi-Kwong Lo Department of Physics and Center of Computational and Theoretical Physics University of Hong Kong Pokfulam Road Hong Kong Center for Quantum Information and Quantum Control Department of Physics and Department of Electrical & Computer Engineering University of Toronto Toronto Ontario M5S 3G4 Canada

Transmission of photons through open-air or optical fibers is an important primitive in quantum-information processing. Theoretical descriptions of this process often consider single photons as information carriers and thus fail to accurately describe experimental implementations where any number of photons may enter a detector. It has been a great challenge to bridge this big gap between theory and experiments. One powerful method for achieving this goal is by conceptually squashing the received multiphoton states to single-photon states. However, until now, only a few protocols admit a squash model; furthermore, a recently proven no-go theorem appears to rule out the existence of a universal squash model. Here we show that a necessary condition presumed by all existing squash models is in fact too stringent. By relaxing this condition, we find that, rather surprisingly, a universal squash model actually exists for many protocols, including quantum key distribution, quantum state tomography, Bell's inequality testing, and entanglement verification.

关键词： PHOTONS EINSTEIN-Podolsky-Rosen experiment OPTICAL fibers TOMOGRAPHY OPTICAL communications

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A Multi-Robot System for Dome Inspection and Maintenance: Concept and Stability Analysis

A Multi-Robot System for Dome Inspection and Maintenance: Co...

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IEEE International Conference on Robotics and Biomimetics

作者： A. Nejadfard H. Moradi M. Nili Ahmadabadi School of Electrical and Computer Engineering the University of Tehran Control and Intelligent Processing Center of Excellence at the Electrical and Computer Engineering Department at the University of Tehran

ISBN: (纸本)9781457721366

In this paper a novel approach based on multi-robot cooperation is introduced for inspection and repair of dome structures. In this application, three robots which can be extended to more, connect to each other by three strings and cooperate such that all the robots are stable and at least one robot have access to all parts of the dome. The mathematical model of the system is derived and a systematic methodology is developed to find an optimal configuration, based on minimizing the strings' tensions or maximizing the stability, using Particle Swarm Optimization (PSO) algorithm and quadratic programming. The simulation results prove that there exists a stable path to fully sweep the surface of a dome. The experimental results on a small scale prototype validate these findings.

关键词： dome Stability analysis Dome Device Component Robot Robot System optimal configuration Cosmic strings Inspection stalls(animals)

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Functional Requirement and Realization of Regional Smart Grid Energy Management System

Functional Requirement and Realization of Regional Smart Gri...

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第八届IEEE信息与自动化国际会议(ICIC 2011)

作者： Xilin Zhang Xiaojuan Han Xiaohua Wan Shuo Wang Dispatching Center Changchun Power Supply Company Changchun 130012China Department of Control and Computer Engineering North China Electrical Power University Beijing 10220 Department of Engineering Changchun Huaxin Automation Engineering Co. LTD Changchun130012China Transformation Controlled Company Jilin Electric Power Transmission Engineering Corporation Changchu

ISBN: (纸本)9781457702686

From the requirement of satisfying regional monitoring and scheduling management under the characteristics of the regional grid and the connotation of intelligent grid as well as regulation and control integration management,power quality on-line monitoring of EMS in regional intelligent grid and optimized operation setting checking conditions of arc-suppression coil are discussed in this paper. Load forecast data sources and functional requirements of SCADA picture for engineering design and realization method are provided in this paper.

关键词： arc-suppression coil energy management system load forecast power quality smart grid Energy management systems load forecasting Smart grids functional requirements Power quality ON-LINE MONITORS design engineering

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Improved Servomechanism control Design – Nonswitching Case

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IFAC Proceedings Volumes 2011年第1期44卷 8614-8619页

作者： Aurélio T. Salton Zhiyong Chen Minyue Fu School of Electrical Engineering and Computer Science The University of Newcastle Australia Pontifícia Universidade Católica do Rio Grande do Sul Brazil State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology China Department of Control Science and Engineering Zhejiang University China

Abstract This paper attempts to achieve time-optimal performance for servomechanisms via a practical feedback control law. An improvement over the traditional Proximate Time Optimal Servomechanism (PTOS) is proposed in order to eliminate the conservatism present in the controller. The original PTOS switches from the nonlinear approximation of Time Optimal control (TOC) to a linear controller as the system approaches the reference point. This switching results in a compromise in performance inasmuch as the linear controller is not sufficiently aggressive to settle the system output with acceptable levels of overshoot. The proposed controller eliminates the necessity of the switching function by making use of an elaborate nonlinear control law. Simulations and experimental results show that the proposed design achieves levels of performance comparable to that of the theoretical TOC.

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Robotic test bed for autonomous surface exploration of Titan, Mars, and other planetary bodies

Robotic test bed for autonomous surface exploration of Titan...

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IEEE Conference on Aerospace

作者： Wolfgang Fink Mark A. Tarbell Roberto Furfaro Linda Powers Jeffrey S. Kargel Victor R. Baker Jonathan Lunine Visual and Autonomous Exploration Systems Research Laboratory Division of Physics Mathematics and Astronomy California Institute of Technology Pasadena CA USA Visual and Autonomous Exploration Systems Research Laboratory Departments of Electrical & Computer Engineering Biomedical Engineering and Ophthalmology and Vision Science University of Arizona Tucson Tucson AZ USA Systems and Industrial Engineering Department University of Arizona Tucson Tucson AZ USA Department of Electrical & Computer Engineering University of Arizona Tucson Tucson AZ USA Department of Hydrology and Water Resources University of Arizona Tucson Tucson AZ USA Lunar and Planetary Laboratory University of Arizona Tucson Tucson AZ USA

Tier-scalable robotic reconnaissance missions are called for in extreme space environments, including planetary atmospheres, surfaces (both solid and liquid), and subsurfaces (e.g., oceans), as well as in potentially hazardous or inaccessible operational areas on Earth. Such future missions will require increasing degrees of operational autonomy: (1) Automatic mapping of an operational area from different vantages (i.e., spaceborne, airborne, surface, subsurface); (2) automatic sensor deployment and sensor data gathering; (3) automatic feature extraction and target/region-of-interest/anomaly identification within the mapped operational area; (4) automatic target prioritization for follow-up or close-up (in-situ) examination; and (5) subsequent automatic, targeted deployment and navigation/relocation of agents/sensors (e.g., to follow up on transient events). We report on recent progress in developing an Earth-based (outdoors) robotic test bed for Tier-scalable Reconnaissance at the University of Arizona and Caltech for distributed, science-driven, and significantly less constrained (compared to state-of-the-art) reconnaissance of prime locations on a variety of planetary bodies, with particular focus on Saturn's moon Titan with its methane/hydrocarbon lakes and Mars. The test bed currently comprises several computer-controlled robotic surface vehicles, i.e., rovers and lake landers/boats equipped with a variety of sensors. To achieve a fully operational Tier-scalable Reconnaissance test bed, aerial platforms will be integrated as a next step. The robotic surface vehicles can be interactively or automatically controlled from anywhere in the world in near real-time via the Internet. The test bed enables the implementation, field-testing, and validation of algorithms and strategies for navigation, exploration, sensor deployment, sensor data gathering, feature extraction, anomaly detection, and science goal prioritization for autonomous planetary exploration. Furthermor

关键词： Robot sensing systems Sea surface Cameras Reconnaissance Boats Lakes

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Effective Supervised Classification of fMRI Activation Maps between Populations by Spatial Descriptors

Effective Supervised Classification of fMRI Activation Maps ...

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Iranian Machine Vision and Image Processing (MVIP)

作者： Shaghayegh Eshaghian Gholam-Ali Hossein-Zadeh Hamid Soltanian-Zadeh Control and Intelligent Processing Center of Excellence School of Electrical and Computer Engineering University of Tehran Tehran Iran Image Analysis Laboratory Radiology Department Henry Ford Hospital Detroit MI USA

The major obstacle in discrimination between different groups of subjects in a common cognitive state, by functional Magnetic Resonance Imaging (fMRI), has been the high inter- subject functional and anatomical variability in the spatial patterns of brain activity. To overcome this, we have used two types of spatial descriptors that characterize the brain regions of interest (ROIs) involved in the cognitive tasks. They include, firstly three-dimensional invariant moment descriptors (3-DMIs), and secondly k-dimensional feature vectors based on concentric spheres. Both types of descriptors are applied to analyze the spatial patterns of cognitive activity of a challenging task and then to classify them across two different subject groups. SVM classifiers along with sequential floating forward feature selection technique are applied to the extracted descriptors of each ROI across the subjects. Our method is applied to experimental fMRI data with the aim of discriminating mental status of heroin IV (Intravenous) abusers and from of those in control subjects in a visual cue task which can induce drug craving. Our results demonstrate that 3-D texture of activation maps provide a good discrimination (with high accuracy) between healthy and addict group.

关键词： Feature extraction Accuracy Drugs Brain Support vector machine classification Visualization Humans

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