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International Conference on electrical Machines, ICEM

作者： Fernando J. T. E. Ferreira Anibal T. de Almeida Institute of Systems and Robotics University of Coimbra Coimbra Portugal Department of Electrical Engineering Engineering Institute of Coimbra Coimbra Portugal

Due to poor motor system design or excessive safety factors, it is common to find oversized three-phase, squirrel-cage, induction motors, i.e., with a rated power higher than that actually necessary by the driven equipment. In those cases, if the oversizing level is significant, besides the unnecessary additional capital investment, the motors operate with poor efficiency and power factor, being an undesirable situation for the user. In this paper, an overview on the in-field motor load estimation methods is offered, being its importance evidenced. The simplest, low-cost, in-field methods to indirectly estimate the motor load are analyzed, being the focus on methods based upon the motor current, slip, and input power. Such methods require simple measurements with relatively low-cost equipment and information from the motor nameplate, manufacturers, catalogues, and/or databases, having a fair accuracy if applied to specific motors and load ranges. Some improvements in those methods are proposed to increase their accuracy, including combined solutions. A new definition of ldquouseful accuracyrdquo is introduced, for evaluation of the effectiveness or adequacy of the motor load estimation methods.

关键词： Induction motors Voltage Reactive power Costs Safety devices Investments Robots Rotors Acoustic noise Temperature

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On the Design of Rotorcraft Landing Controllers

On the Design of Rotorcraft Landing Controllers

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2008 Mediterranean Conference on Control Automation, vol.4

作者： Pedro Serra Rita Cunha Carlos Silvestre Department of Electrical Engineering and Computer Science and Institute of Systems and Robotics Instituto Superior Technico Lisboa Portugal

This paper describes a solution to the problem of landing a helicopter autonomously. The methodology used poses the problem as a discrete time path following control problem where a conveniently defined error state space model of the helicopter is modified to include the aerodynamic effects of flying within close proximity to the ground. An affine parameter-dependent model representation is adopted that describes the helicopter linearized error dynamics for the predefined landing operating region. A state feedback H{sub}2 control problem for affine parameter-dependent systems is posed and solved using Linear Matrix Inequalities (LMIs). The resulting nonlinear controller is implemented using the D-methodology and dynamic weights to enforce bandwidth constraints on the actuators. The effectiveness of the proposed controller with and without dynamic weights on the actuation is assessed in simulation using the full nonlinear dynamic model of a small-scale helicopter.

关键词： Automation Conferences

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A dynamic estimator on SE(3) using range-only measurements

A dynamic estimator on SE(3) using range-only measurements

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IEEE Conference on Decision and Control

作者： A. Alcocer P. Oliveira A. Pascoal R. Cunha C. Silvestre Institute for Systems and Robotics and the Department of Electrical Engineering and Computers Instituto Superior Técnico Lisboa Portugal

ISBN: (纸本)9781424431236

This paper addresses the problem of estimating the attitude and position of a rigid body when the available measurements consist only of the relative distances between a set of body fixed beacons and a set of Earth fixed landmarks. The proposed solution is given in terms of a dynamical system evolving on the Special Euclidean group SE(3), the trajectories of which are shown to locally converge to the actual attitude and position of the rigid body. Local asymptotic stability of the dynamical system is proven by using a suitable Lyapunov function, under the assumption that there is a set of noncoplanar landmarks and beacons. Simulation results are shown to illustrate the behaviour of the proposed estimator.

关键词： Position measurement Distance measurement Earth Computer vision Maximum likelihood estimation Cost function Attitude control Asymptotic stability Lyapunov method Wireless networks

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Output-feedback control for almost global stabilization of fully-actuated rigid bodies

Output-feedback control for almost global stabilization of f...

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IEEE Conference on Decision and Control

作者： David Cabecinhas Rita Cunha Carlos Silvestre Department of Electrical Engineering and Computer Science and Institute for Systems and Robotics Instituto Superior Técnico Lisboa Portugal

ISBN: (纸本)9781424431236

This paper addresses the problem of stabilizing a fully-actuated rigid body. The problem is formulated considering the natural space for rigid body configurations, the Special Euclidean group SE(3). The proposed solution consists of an output-feedback controller for force and torque actuation that guarantees almost global asymptotic stability of the desired equilibrium point. As such the equilibrium point is a stable attractor for all initial conditions except for those in a nowhere dense set of measure zero. As an additional feature, the controller is required to verify prescribed bounds on the actuation.

关键词： Control systems Force control Geometry Asymptotic stability US department of Transportation Torque control State-space methods Quaternions Adaptive control Robot kinematics

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Generalized MMF space harmonics and performance analysis of combined multiple-step, star-delta, three-phase windings applied on induction motors

Generalized MMF space harmonics and performance analysis of ...

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International Conference on electrical Machines, ICEM

作者： M. V. Cistelecan F. J. T. E. Ferreira H. B. Cosan Research Institute of Electrical Machines Bucharest Romania Institute of Systems and Robotics University of Coimbra Coimbra Portugal Department of Electrical Engineering Engineering Institute of Coimbra Coimbra Portugal Department of Electrical Engineering Ege University Izmir Turkey

In the paper it is developed a complete theory and method of analysis of combined star-delta three-phase windings from the point of view of MMF spatial harmonics content. The developed method is verified by means of experimental tests in a motor with a specially designed stator winding, allowing multiple-step air-gap flux regulation.

关键词： Performance analysis Induction motors Magnetic flux Coils Machine windings Air gaps Magnetic separation Magnetic analysis Harmonic analysis Stator windings

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IEEE Transactions on Haptics: Editorial

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IEEE Transactions on Haptics 2008年第1期1卷 2-8页

作者： Edward Colgate, J. Lederman, Susan Prattichizzo, Domenico Barbagli, Federico Basdogan, Cagatay Buss, Martin Ernst, Marc Frisoli, Antonio Gillespie, Brent Grant, Danny Harders, Matthias Hayward, Vincent Jones, Lynette Kajimoto, Hiroyuki Kappers, Astrid Kheddar, Abderrahmane Lin, Ming C. MacLean, Karon Miller, Brian Noma, Haruo Okamura, Allison M. O'Malley, Mareia Ryu, Jeha Tan, Hong Z. Yokokohji, Yasuyoshi Department of Psychology School of Computing Queen's University Canada IEEE Robotics and Automation Society Tübingen Germany Stanford University's Computer Science Department Tübingen Germany Institute of Automatic Control Engineering Technische Universität München Germany Independent Research Group Multisensory Perception and Action Max Planck Institute for Biological Cybernetics Tübingen Germany Department of Applied Mechanics SSSA Japan Research Division Virtual Reality and Telerobotic Systems PERCRO Laboratory Japan Department of Mechanical Engineering Japan Department of Robotics McGill University Canada Computer Vision Lab ETH Zurich Japan Virtual Reality in Medicine Group Japan IEEE CS/RAS Technical Committee on Haptics Japan Department of Electrical and Computer Engineering McGill University Canada Department of Mechanical Engineering MIT Japan University of Electro-Communications Japan Department of Physics and Astronomy Utrecht University Netherlands University of Evry France Chapel Hill United States Department of Computer Science University of British Columbia Canada ATR Knowledge Science Lab United Kingdom Department of Mechanical Engineering Denmark Johns Hopkins University United States Laboratory for Computational Sensing and Robotics United Kingdom Engineering Research Center for Computer-Integrated Surgical Systems and Technology United States Mechanical Engineering and Materials Science Department Rice University United States Korea Republic of Department of Electrical and Computer Engineering Mechanical Engineering and Psychological Sciences Purdue University United States Department of Mechanical Engineering and Science Graduate School of Engineering Kyoto University Japan

No abstract available

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Annual business and news:: Beginning the 31st year of the Journal of Guidance, Control, and Dynamics

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2008年第1期31卷 1-1页

作者： Schmidt, George T. Aeronautics and Astronautics Massachusetts Institute of Technology (MIT) AIAA Institute of Electrical and Electronics Engineers Russian Federation Academy of Navigation and Motion Control Department of Mechanical and Aerospace Engineering and Engineering Mechanics University of Missouri-Rolla(UMR) Lockheed Electronics Company Center for Space Research University of Texas Austin United States Wright Laboratory Eglin Air Force Base UMR AIAA Guidance Navigation and Control Technical Committee American Automatic Control Council Lockheed Martin Aeronautics Company Palmdale CA United States C4ISR and Unmanned Air Vehicle (UAV) Programs for Air Vehicle Sciences and Systems Accreditation Board Engineering and Technology Inc./Aeronautical National Technical Committee on Guidance Navigation and Control Department of Mechanical and Aerospace Engineering University at Buffalo State University of New York (SUNY) AIAA Technical Committee on GN and C Air Vehicles Directorate Air Force Research Laboratory (AFRL) Wright-Patterson Air Force Base Space Access and Hypersonic Vehicle Guidance and Control Group Control Science Center of Excellence AFRL AIAA Technical Committee on Guidance Navigation and Control Department of Mechanical and Aeronautical Engineering University of California (UC) Davis United States Boeing Company Modernized Flight Control System for the Apache Longbow AIAA Institute of Electrical and Electronics Engineers AHS Jet Propulsion Laboratory California Institute of Technology Boeing Company Flight Sciences and Advanced Design Group Guidance Navigation and Control (GN and C) Systems Engineer Distributed Space Systems NASA Goddard Space Flight Center (GSFC) AIAA GN and C Technical Committee Department of Aerospace Engineering and Engineering Mechanics University of Texas Austin United States Institute of Navigation American Astronautical Society AIAA Guidance Navigation (GN and C) and Control Technical Committee Department of Aerospace Engineering Iowa State University Iowa

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Electric motor standards, ecodesign and global market transformation

Electric motor standards, ecodesign and global market transf...

引用

Annual Meeting Industrial and Commercial Power systems Technical Conference

作者： Anibal T. de Almeida Fernando J. T. E. Ferreira Joao A. C. Fong Conrad U. Brunner Institute of Systems and Robotics University of Coimbra Coimbra Portugal Department Electrical Engineering Engineering Institute of Coimbra Coimbra Portugal Sustainable Energy Advisors AB International Zurich Switzerland

The use-phase cost of most industrial electric motors, namely the consumed electrical energy, dominates by far their overall life-cycle cost. Because electric motors use about 70% of the total industrial electricity use, they present attractive opportunities to save a huge amount of electricity in a cost- effective way, and contribute to mitigate climate change. The lack of global efficiency classes has prevented the large-scale adoption of high efficiency motors in most countries around the world. This paper addresses the most relevant electric motor efficiency-related international standards, including minimum efficiency requirements and a new efficiency classification standard, which have a profound impact on motor market transformation, being a powerful tool to reduce electric motor systems consumption. Moreover, the final results and conclusions of a European study to identify and recommend ways to improve the life-cycle environmental performance of electric motors at their design phase are presented, focusing life- cycle cost assessment of standard and best available electric motor technologies. It was found that if high efficiency or premium class motors replace standard efficiency class motors, significant reductions in the environmental impact will be achieved.

关键词： Induction motors Standards Marketing and sales IEC Energy efficiency Europe Electricity

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A Geometric Approach to Strapdown Magnetometer Calibration in Sensor Frame *

引用

IFAC Proceedings Volumes 2008年第1期41卷 172-177页

作者： J.F. Vasconcelos G. Elkaim C. Silvestre P. Oliveira B. Cardeira Institute for Systems and Robotics (ISR) Instituto Superior Técnico Lisbon Portugal. Tel:351-21-8418054 Fax:351-21-8418291 Department of Computer Engineering University of California SantaCruz 1156 High St. SantaCruz CA 95064

In this work a new algorithm is derived for the onboard calibration of three-axis strapdown magnetometers. The proposed calibration method is written in the sensor frame, and compensates for the combined effect of all linear time-invariant distortions, namely soft iron, hard iron, sensor non-orthogonality, bias, among others. A Maximum Likelihood Estimator (MLE) is formulated to iteratively find the optimal calibration parameters that best fit to the onboard sensor readings, without requiring external attitude references. It is shown that the proposed calibration technique is equivalent to the estimation of an ellipsoidal surface, and that the sensor alignment matrix is given by the solution of the orthogonal Procrustes problem. Good initial conditions for the iterative algorithm are obtained by a suboptimal batch least squares computation. Simulation and experimental results with low-cost sensors data are presented, supporting the application of the algorithm to autonomous vehicles and other robotic platforms.

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Visual P300-based BCI to steer a wheelchair: A Bayesian approach

Visual P300-based BCI to steer a wheelchair: A Bayesian appr...

引用

Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Gabriel Pires Miguel Castelo-Branco Urbano Nunes Department of Electrical Engineering Instituto Politécnico de Tomar Tomar Portugal Institute for Systems and Robotics University of Coimbra Coimbra Portugal Biomedical Institute for Research in Light and Image (IBILI) University of Coimbra Portugal

This paper presents a new P300 paradigm for brain computer interface. Visual stimuli consisting of 8 arrows randomly intensified are used for direction target selection for wheelchair steering. The classification is based on a Bayesian approach that uses prior statistical knowledge of target and non-target components. Recorded brain activity from several channels is combined with a Bayesian sensor fusion and then events are grouped to improve event detection. The system has an adaptive performance that adapts to user and P300 pattern quality. The classification algorithms were obtained offline from training and then validated offline and online. The system achieved a transfer rate of 7 commands/min with 95% false positive classification accuracy.

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