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arXiv 2017年

作者： González-Avilés, J.J. Guzmán, F.S. Fedun, V. Verth, G. Shelyag, S. Regnier, S. Laboratorio de Inteligencia Artificial y Supercómputo Instituto de Física y Matemáticas Universidad Michoacana de San Nicolás de Hidalgo. MoreliaMichoacán Mexico Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom School of Mathematics and Statistics University of Sheffield SheffieldS3 7RH United Kingdom Department of Mathematics Physics and Electrical Engineering Northumbria University Newcastle upon TyneNE1 8ST United Kingdom

Using simulated data-driven three-dimensional resistive MHD simulations of the solar atmosphere, we show that 3D magnetic reconnection may be responsible of the formation of jets with characteristics of Type II spicules. For this, we numerically model the photosphere-corona region using the C7 equilibrium atmosphere model. The initial magnetic configuration is a 3D potential magnetic field, extrapolated up to the solar corona region from a dynamic realistic simulation of solar photospheric magnetoconvection model which is mimicking quiet-Sun. In this case we consider a uniform and constant value of the magnetic resistivity of 12.56 Ω m. We have found that formation of the jet depends on the Lorentz force, which helps to accelerate the plasma upwards. Analyzing various properties of the jet dynamics, we found that the jet structure shows Doppler shift near to regions with high vorticity. The morphology, upward velocity, covering a range up to 130 km s−1, and timescale formation of the estructure between 60 and 90 s, are similar to those expected for Type II spicules. Copyright © 2017, The Authors. All rights reserved.

关键词： Magnetohydrodynamics

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Prediction of subharmonic oscillation in switching regulators with integrative feedback loops

Prediction of subharmonic oscillation in switching regulator...

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International Symposium on Circuits and systems

作者： Abdelali El Aroudi GAEI Research Center Department of Electronics Electrical Engineering and Automatic Control Universitat Rovira i Virgili Tarragona Spain

ISBN: (纸本)9781479953424

This paper investigates the effect of the integrator gain on subharmonic oscillation boundary in switching converters with fixed frequency pulse width modulation (PWM) with an integrative feedback loop. First, the exact state-space switched model of the converter is revisited and then a closed-form expression for predicting this phenomenon is presented. The use of this expression is illustrated by means of two different examples f switching converters. While in voltage mode control, the integral action can be ignored for predicting subharmonic oscillation, it is shown the integral action in the current loop has a significant effect on this phenomenon.

关键词： Oscillators Switches Light emitting diodes Numerical models Time-domain analysis Stability analysis Steady-state

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Topology identification and design of distributed integral action in power networks

Topology identification and design of distributed integral a...

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American control Conference

作者： Xiaofan Wu Florian Dorfler Mihailo R. Jovanovic Department of Electrical and Computer Engineering University of Minnesota Minneapolis 55455 USA Automatic Control Laboratory at ETH Zurich Switzerland

ISBN: (纸本)9781467386838

Recently distributed integral controllers relying on averaging and communication have been proposed as effective means for optimal frequency regulation in power systems, load balancing of network flows, and as natural extensions to static consensus controllers. Typically, only the questions of stability, disturbance rejection, and steady-state resource allocation are addressed in the literature, and the problems of transient performance and optimal communication network design remain open. In this paper we consider the optimal frequency regulation problem and propose a principled heuristic to identify the topology and gains of the distributed integral control layer. We employ an l1-regularized H2-optimal control framework as a means for striking a balance between network performance and communication requirements. The resulting optimal control problem is solved using the alternating direction method of multipliers algorithm. For the IEEE 39 New England benchmark problem, we demonstrate that the identified sparse and distributed integral controller can achieve reasonable performance relative to the optimal centralized controller. Interestingly, the identified control architecture is directed and correlates with the generator rotational inertia and cost coefficients.

关键词： topology identification Alternating direction method of multipliers distributed PI-control power systems sparsity-promoting optimal control

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Subspace Identification of Local 1D Homogeneous systems

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IFAC-PapersOnLine 2015年第28期48卷 892-896页

作者： Yu, Chengpu Verhaegen, Michel Hansson, Anders Delft Center for Systems and Control Delft University Delft2628CD Netherlands Division of Automatic Control Department of Electrical Engineering Linkoping University Sweden

This paper studies the local subspace identification of 1D homogeneous networked systems. The main challenge lies at the unmeasurable interconnection signals between neighboring subsystems. Since there are many unknown inputs to the concerned local system, the corresponding identification problem is semi-blind. To cope with this problem, a nuclear norm optimization based subspace identification is presented, which is carried out for solving the Markov parameters of a locally lifted system, followed by determining the system matrices of a single subsystem. In the step of Markov parameter estimation, we form a nuclear norm regularized optimization problem which can well handle the adverse effects of the unknown system inputs as long as the number of unknown system inputs is relatively small. In the step of system realization, we again derive a nuclear norm regularized optimization formulation which can cope with the under-determinedness of the realization problem. In the end, the overall identification algorithm is summarized. © 2015

关键词： Parameter estimation Markov processes Identification algorithms Identification problem Markov parameters Rank constraints Regularized optimization problems Regularized optimizations Subspace identification System realization

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Discrete-time indirect adaptive control of a class of single state systems using concurrent learning for parameter adaptation

Discrete-time indirect adaptive control of a class of single...

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IEEE International Symposium on Intelligent control (ISIC)

作者： Ouboti Djaneye-Boundjou Raul Ordonez Electrical Engineering Control Systems at the University of Dayton Dayton OH USA Department of Electrical and Computer Engineering University of Dayton Dayton OH USA

ISBN: (纸本)9781509020522

We have previously showed that it is possible to achieve parameter identification of discrete-time structured uncertainties without requiring persistency of excitation when using Concurrent Learning. Instead, granted a less restrictive condition compared to that of persistency of excitation is verified, exponential convergence of parameter estimates to their true values ensues. The present study applies the previously developed discrete-time Concurrent Learning adaptation law within a control loop for discrete-time adaptive control of a discrete-time single-state plant containing structured uncertainties. Provided that the same condition as for the standalone estimation is met, we can prove exponential convergence of the tracking error and parameter error to zero without necessitating persistency of excitation.

关键词： Uncertainty Adaptive control Convergence Estimation Rail to rail inputs Lyapunov methods control systems

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On Topological Conditions to Maintain Leader-Follower Connectivity in Double-Integrator Multi-Agent systems

On Topological Conditions to Maintain Leader-Follower Connec...

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Mediterranean Conference on control and Automation

作者： Philipp N. Kohler Dimos V. Dimarogonas Institute for Systems Theory and Automatic Control (IST) University of Stuttgart ACCESS Linnaeus Center School of Electrical Engineering KTH Royal Institute of Technology

ISBN: (纸本)9781467383479

In this work, a set of sufficient conditions that guarantee consensus towards a pre-specified target state in double-integrator leader-follower proximity-based networks are derived. Since only the leader agents are aware of the global objective and proximity-based communication between agents is considered, the follower agents must not lose contact to the leaders. We establish a connectivity analysis framework which is used to show that the initial network topology is maintained if the ratio of leaders-to-followers and the magnitude of the goal attraction force experienced by the leaders are below certain bounds. Various network topologies are examined, starting from a complete graph and extending to incomplete graphs. The theoretical results are illustrated by simulations.

关键词： Network topology Agents Multi-agent systems Leaders Awareness Connectivity analysis Leadership simulating EARTHQUAKE MAGNITUDE

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Automated particle swarm optimization based PID tuning for control of robotic arm

Automated particle swarm optimization based PID tuning for c...

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IEEE National Conference on Aerospace and Electronics (NAECON)

作者： Ouboti Djaneye-Boundjou Xingsheng Xu Raúl Ordóñez Electrical Engineering (Control Systems) University of Dayton Dayton OH USA Department of Electrical and Computer Engineering University of Dayton Dayton OH USA

In this paper, we revisit the Proportional-Integral-Derivative (PID) controller design for torque control of robotic manipulators, for which, appropriate tuning of the said controller could prove very burdensome, especially with increasing degrees-of-freedom (DOF) and/or when designing a Multi-Input Multi-Output (MIMO) PID controller. That is, when generating and tuning matrix P-I-D gains as opposed to single values, in order to take in account possible coupling effects between involved joints. We tackle both joint space and workspace PID control tuning problems for reference tracking from an optimization standpoint. Using a previously developed stable Adaptive Particle Swarm Optimizer, we are able to automatically and systematically tune P-I-D gains, be it as single gain values or gain matrices, while optimizing a cost or fitness function. The aforesaid cost function can be arranged to feature various aggregated performance measures, `normalized' so as to overcome differences in scale if any. Taking in account some practical limitations, a 2-DOF arm is used here as a case study. Numerical simulations are provided to substantiate the adequacy of our method.

关键词： Tuning Manipulators Robot kinematics Algorithm design and analysis PD control Particle swarm optimization

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Linear Precoding Design for MIMO-PLC systems

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Tsinghua Science and Technology 2015年第2期20卷 155-163页

作者： Jisheng Peng the State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua Uinversity

In this paper, we consider the design of linear precoding in Multiple Input Multiple Output （MIMO） Power Line Communication （PLC） systems with finite-alphabet input. First, we derive mutual information of MIMO-PLC systems with impulsive noise. Considering the non-concavity of the objective function and the low-cost requirement of PLC systems, we choose the lower bound of the mutual information as the objective function. Subsequently, we propose a novel approach to design the precoding scheme to reduce computational complexity. Specifically, our work primarily includes the following two contributions：（1） We design the right unitary matrix that is a product of two fixed unitary matrices, which only depends on the modulation mode. Hence, the results can be saved and require less computations. （2） For the power allocation matrix, we first reduce the space of power allocation using constraints of the optimal power allocation policy. Consequently, we propose a non-linear search method to obtain the optimal power allocation in small space. In regards to the computational complexity of the analysis, we conclude that the proposed precoding matrix design scheme has low complexity and is easy to implement. Moreover, the numerical results are proven to demonstrate the performance of the proposed precoding design scheme.

关键词： precoding design MIMO-PLC impulsive noise finite-alphabet input

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Oscillating Water Column control and Monitoring

Oscillating Water Column Control and Monitoring

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OCEANS MTS/IEEE Monterey (Conference)

作者： Izaskun Garrido Aitor J. Garrido Jon Lekube Erlantz Otaola Edorta Carrascal Automatic Control Group Department of Automatic Control and Systems Engineering EUITI de Bilbao University of the Basque Country Automatic Control Group - ACG. Inst. of Research and Development of Processes Dept. Aut. Control and Systems Eng. University of the Basque Country (UPV/EHU)

ISBN: (纸本)9781509015276

This article covers research into cost reduction pathways for wave energy. The primary focus is the development and test of reliable and controllable power take-off (PTO) technology for oscillating water column converters (OWC). This is highly relevant to the ocean energy challenge. Extensive testing via data of the NEREIDA MOWC demonstration project, a breakwater wave plant located in the Basque location of Mutriku, using Wells turbines and Doubly Fed Induction (DFIG) generators is proposed to advance wave energy converter (WEC) devices. The control tests involve the integration of the PTO technology within a new variable controller for OWC wave power generation plants. Due to the nature of the control law, it allows monitoring faults caused by parametrical errors or system disturbances. The reliability tests by means of analysing the electrical signals have been conceived as conditioning monitoring, detection of mechanical faults and hardware damaging also fulfil a secondary aim for the reduction of maintenance cost and unscheduled downtime during operation of OWC plants.

关键词： Modelling and Simulation control Wave Energy OWC Condition Monitoring

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Input concentration estimation for an anaerobic digestion process using EKF and SM observers. A comparative study

Input concentration estimation for an anaerobic digestion pr...

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International Conference on System Theory, control, and Computing (ICSTCC)

作者： Marian Barbu George Ifrim Emil Ceanga Sergiu Caraman Emil Petre Dan Selisteanu Department of Automation and Electrical Engineering “Dunarea de Jos” University Galati Romania Department of Automatic Control University of Craiova Craiova Romania

ISBN: (纸本)9781509027217

It is well known that in the case of the wastewater treatment bioprocesses, including anaerobic digestion process, usually, the complete knowledge of inputs is not available and therefore the implementation of the control laws becomes a difficult problem. Therefore, in the sequel, for the above mentioned process two observer structures, able to estimate the unknown concentration of the input will be presented and analyzed. The paper deals with a comparative analysis of two types of observers: a stochastic one - Extended Kalman Filter and a deterministic one - Sliding Mode Observer. The estimation methods are analyzed in realistic frame taking into consideration the presence of the measurement noise but especially the usual variations in the case of an anaerobic digestion process, such as the variation of the maximum growth rate of the microorganisms. The effectiveness of the proposed observers has been validated by numerical simulations.

关键词： Observers Mathematical model Noise measurement Process control Microorganisms Kalman filters

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