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Plant Uncertainty Contribution to QFT Tracking control Design

IFAC Proceedings Volumes 2003年第11期36卷 517-522页

作者： M. Gil-Martínez M. García-Sanz System Engineering and Automation Group Electrical Engineering Department University of La Rioja. Luis de Ulloa 20 26004 Logroño SPAIN. Tf.:+34 941 299496 Automatic Control and Computer Science Department Public University of Navarra. Campus Arrosadía s/n 31006 Pamplona SPAIN Tf.:+34 948 16938

Tracking feedback control trade-offs increase dangerously with arbitrarily large uncertainties in the process model. This is shown by the bounds in the QFT domain. In this context, the paper develops a theory on the contribution of the plant uncertainty to the tracking QFT bounds through a serious study of tracking bound formulas. From this, a methodology for uncertainty fragmentation is developed. It hopes to loosen the bound toughness, or the control design trade-offs. Better feedback benefits can be achieved while reducing the high-frequency amplification of noises and disturbances at the plant input at the same time. Different QFT controllers in a controller-scheduler structure should drive different uncertainty boundaries.

关键词： Quantitative Feedback Theory Robust control Uncertain Dynamical systems

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Extending CSP to detect motor imagery in a four-class BCI

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Journal of Information and Computational Science 2012年第1期9卷 143-151页

作者： Fang, Yonghui Chen, Minyou Zheng, Xufei Harrison, R.F. State Key Laboratory of Power Transmission Equipment and System Security New Technology Chongqing University Chongqing 400044 China School of Electronic and Information Engineering Southwest University Chongqing 400715 China College of Computer Science Sichuan University Chengdu 610065 China Department of Automatic Control and Systems Engineering University of Sheffield United Kingdom

Brain Computer Interface (BCI) provides a direct communication channel from brain to peripheral equipment. Common Spatial Patterns (CSP) is wildly used to extract features for electroencephalogram (EEG). However, basic CSP only suits two-class discrimination and is unable to solve multi-class discrimination problems. This paper proposes a modified CSP method termed Bisearch Common Spatial Patterns (BCSP) to solve a four-class BCI problem. In BCSP, the Fisher's Linear Discriminant Analysis (LDA) is used to discriminate among the four motor imagery tasks. The BCSP can effectively reduce the number of the basic CSP, and thus makes the overall classification procedure more efficient. The Graz BCI data set from the BCI 2008 competition be used to verify the effectiveness of the BCSP. Simulation results show that BCSP has better performance than other extension schemes. © 2012 Binary Information Press January 2012.

关键词： Brain computer interface

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On the Approximation of the Quotient of Two Gaussian Densities for Multiple-Model Smoothing

On the Approximation of the Quotient of Two Gaussian Densiti...

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International Conference on Information Fusion

作者： Yi Liu Xi Li Le Yang Lyudmila Mihaylova Yanbo Xue Department of Electrical and Computer Engineering University of Canterbury Christchurch NZ State Key Lab of Complex Electromagnetic Environment Effects on Electronics and Information Systems National University of Defense Technology Changsha China Department of Automatic Control and System Engineering University of Sheffield Sheffield UK Career Science Lab Beijing China

The quotient of two multivariate Gaussian densities can be written as an unnormalized Gaussian density, which has been applied in some recently developed multiple-model fixed-interval smoothing algorithms. However, this expression is invalid if instead of being positive definite, the covariance of the unnormalized Gaussian density is indefinite (i.e., it has both positive and negative eigenvalues) or undefined (i.e., computing it requires inverting a singular matrix). This paper considers approximating the quotient of two Gaussian densities in this case using two different approaches to mitigate the caused numerical problems. The first approach directly replaces the indefinite covariance of the unnormalized Gaussian density with a positive definite matrix nearest to it. The second approach computes the approximation through solving, using the natural gradient, an optimization problem with a Kullback-Leibler divergence-based cost function. This paper illustrates the application of the theoretical results by incorporating them into an existing smoothing method for jump Markov systems and utilizing the obtained smoothers to track a maneuvering target.

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Programmable Medicine: Autonomous, Ingestible, Deployable Hydrogel Patch and Plug for Stomach Ulcer Therapy

Programmable Medicine: Autonomous, Ingestible, Deployable Hy...

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IEEE International Conference on Robotics and Automation

作者： Alexis du Plessis d'Argentre Samuel Perry Yoshitaka Iwata Haruna Iwasaki Eiji Iwase Assunta Fabozzo Iain Will Daniela Rus Dana D. Damian Shuhei Miyashita Ecole Supérieure d'Electronique de l'Ouest France Department of Electronic Engineering University of York York UK Department of Applied Mechanics Waseda University Japan Hospital of Padua Italy Computer Science and Artificial Intelligence Laboratory MIT USA Department of Automatic Control and System Engineering University of Sheffield UK

Gastric ulcer is a chronic and complex (and often complete) erosion of the stomach wall that happens as a complication of a previous chronic, inflammatory process. It represents a catastrophic situation in which the patient is critical and its conditions need to be treated fast. This study presents a remotely navigatable and deployable ingestible patch and plug for gastric ulcer treatment. The patch/plug structure is made of agarose hydrogel that can change rigidity through hydration and dehydration. When dehydrated, it is rigid and can maintain a folded configuration so it can be ingested as a "pill". This can be guided to the targeted location by a magnetic field, and be deployed instantly by hydration, namely by supplying water from the mouth. Due to the deployable origami design, it exhibits an expansion of 10 times its initial surface area, making the device suitable for the use of dressing a surface as a patch, and filling a hole as a plug.

关键词： Plugs Stomach Navigation Shape Fabrication Robot sensing systems

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Subspace based Nonlinear Multichannel Blind Identification/Equalization

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IFAC Proceedings Volumes 2009年第10期42卷 1692-1697页

作者： Juan C. Gómez Enrique Baeyens Kameshwar Poolla Laboratory for System Dynamics and Signal Processing FCEIA Universidad Nacional de Rosario CIFASIS CONICET Riobamba 245 Bis 2000 Rosario Argentina Department of Systems Engineering and Automatic Control ETSII Universidad de Valladolid Paseo del Cauce s/n 47011 Valladolid Spain Department of Mechanical Engineering University of California at Berkeley 5141 Etcheverry Hall Berkeley CA 94720-1740 USA

A subspace based approach for the blind identification/equalization of nonlinear Single Input Multiple Output (SIMO) time-invariant channels is presented in this paper. The considered models include, but are not limited to, polynomial approximations of nonlinear channels (i.e., Volterra models), which have been used to represent satellite communications, magnetic recording channels, and physiological processes, among other applications. The channel parameters are estimated in closed form, up to a scalar factor, by computing the column space of the output Hankel matrix, via a Singular Value Decomposition (SVD), and then solving a Least Squares (LS) estimation problem also resorting to an SVD. Numerical simulations are used to illustrate the performance of the proposed algorithms.

关键词： Identification Subspace Methods Nonlinear system Communication Channels

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A Hierarchical Architecture for the Coordination of an Ensemble of Steam Generators

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IFAC-PapersOnLine 2020年第2期53卷 11557-11562页

作者： Stefano Spinelli Elia Longoni Marcello Farina Felix Petzke Stefan Streif Andrea Ballarino Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano Italy Istituto di Sistemi e Tecnologie Industriali Intelligenti per il Manifatturiero Avanzato Consiglio Nazionale delle Ricerche Department of Electrical Engineering and Information Technology Technische Universität Chemnitz Automatic Control and System Dynamics Lab

This work presents a hierarchical architecture for the optimal management of an ensemble of steam generators, which needs to jointly sustain a common load. The coordination of independent subsystems is provided by a multi-layer control scheme. A high-level optimizer computes the optimal shares of production to be allocated to single generators. At medium level, a robust tube-based model predictive control (MPC) is proposed to track the time-varying demand of the ensemble using a centralized, but aggregated model, whose order does not scale with the number of subsystems. At low level, decentralized controllers are in place to stabilize the internal boiler pressure. The control architecture enables the dynamic modification of the ensemble configuration and plug and play operations. Simulation results are reported to demonstrate the potentialities of the proposed approach.

关键词： Model predictive optimization-based control Optimization control of large-scale network systems Hierarchical multilevel multi-layer control Steam generator Energy systems

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Feature extraction of motor imagery in BCI with approximate entropy

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Journal of Computational Information systems 2012年第6期8卷 2485-2491页

作者： Fang, Yonghui Chen, Minyou Zheng, Xufei Harrison, Robert F State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Chongqing 400044 China School of Electronic and Information Engineering Southwest University Chongqing 400715 China College of Computer Science Sichuan University Chengdu 610065 China Department of Automatic Control and Systems Engineering University of Sheffield Sheffield United Kingdom

Approximate Entropy (ApEn) is a regularity statistic that quantifies the unpredictability of fluctuations in a time series and can classify complex systems. This study, ApEn is used to extract features from motor imagery Electroencephalogram (EEC) that containing two motor imagery tasks. This method is different from the traditional way to get the character from EEC. Appropriate parameters must been chosen for different dataset. Two datasets are used in this paper. One comes from BCI Competion2003, the other from the lab of Electromagnetic theory and artincal intelligence, Chongqing University. The results show that ApEn can extract different features in left-hand and right-hand motor imagery EEC efficiently. Comparison between ApEn and Fast Fourier Transform (FFT) shows that ApEn has good capability to the two imagery tasks Brain Computer Interface. © 2012 Binary Information Press.

关键词： Electroencephalography

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Hierarchical control scheme for voltage Harmonics Compensation in an islanded droop-controlled microgrid

Hierarchical control scheme for voltage Harmonics Compensati...

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International Conference on Power Electronics and Drive systems (PEDS)

作者： Mehdi Savaghebi Josep M. Guerrero Alireza Jalilian Juan C. Vasquez Tzung-Lin Lee Center of Excellence for Power System Automation and Operation Iran University of Science and Technology Iran Department of Automatic Control and Industrial Informatics Technical University of Catalonia Spain Institute of Energy Technology University of Aalborg Denmark Department of Electrical Engineering National Sun Yat-sen University Taiwan

In this paper, a microgrid hierarchical control scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controller mainly consists of active and reactive power controllers, voltage and current controllers, and virtual impedance loop. A novel virtual impedance structure is proposed to achieve proper sharing of non-fundamental power among the microgrid DGs. The secondary level is designed to manage compensation of voltage harmonics at the microgrid load bus (LB) to which the sensitive loads may be connected. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values is directed by the secondary level. These functions are achieved by sending proper control signals to the local controllers. The simulation results show the effectiveness of the proposed control scheme.

关键词： Harmonic analysis Voltage control Power harmonic filters Impedance Frequency control Resistance

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SUGAR FACTORY SIMULATOR FOR OPERATORS TRAINING

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IFAC Proceedings Volumes 2006年第6期39卷 259-264页

作者： A. Merino R. Mazaeda R. Alves A. Rueda L.F. Acebes de Prada C. Center of Sugar Technology.University of Valladolid. Edificio Alfonso VIII. Real de Burgos s/n. Valladolid 47011. Spain Department of System Engineering and Automatic Control University of Valladolid. Faculty of Sciences. c/ Real de Burgos s/n 47011 Valladolid Spain

This paper presents the main features of a sugar factory training simulator currently used for control room operators training. This simulator is based on a realistic distributed real time simulation of the whole factory and in a mimic of the control system. It allows the familiarization of the operators with the process and control system as well as with the process information that they use in the real plant. The main aims of the simulator are: (i) to guarantee operators knowledge of the process, and its control system; (ii) to test potentially dangerous situations and (iii) to identify possible problems sources and learn to correct them.

关键词： Training Simulators Physical Modelling Distributed simulation Sugar Factories

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On the Gaussian Filtering for Nonlinear Dynamic systems Using Variational Inference

On the Gaussian Filtering for Nonlinear Dynamic Systems Usin...

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International Conference on Information Fusion

作者： Yi Liu Xi Li Le Yang Lyudmila Mihaylova Ji Li Department of Electrical and Computer Engineering University of Canterbury Christchurch NZ State Key Lab of Complex Electromagnetic Environment Effects on Electronics and Information Systems National University of Defense Technology Changsha China Department of Automatic Control and System Engineering University of Sheffield Sheffield UK Locaris Electronic Technology Co. Ltd Zhengzhou China

ISBN: (数字)9781737749769

ISBN: (纸本)9798350371420

This paper introduces a new variational Gaussian filtering approach for estimating the state of a nonlinear dynamic system. We first assume that the predictive distribution of the state is Gaussian and derive an iterative method for updating the state posterior in the natural parameter space through KullbackLeibler divergence minimization. The obtained update rule is the same as that of the conjugate-computation variational inference technique in Bayesian learning. The derivation here is simpler and more insightful. We then impose a Wishart prior on the inverse of the state prediction covariance to take into account the impact of approximating the state predictive distribution using a Gaussian density on the state posterior estimation. The prediction covariance is identified jointly with the state using variational inference and the established state posterior update rule to achieve the desired Gaussian filtering. Simulation study examines the performance of the proposed filtering framework in target tracking based on bearing and range measurements.

关键词： Target tracking Smoothing methods Filtering Estimation Filtering algorithms Prediction algorithms Minimization Nonlinear dynamical systems Bayes methods Iterative methods

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