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26th International Conference on Parallel Computational Fluid Dynamics, ParCFD 2013

作者： Han, Xiangxi Zhao, Chengbi Tang, Youhong Chen, Xiaoming Lin, Wei Sammut, Karl Department of Naval Architecture and Ocean Engineering School of Civil Engineering and Transportation South China University of Technology Guangdong 510641 China Centre for Maritime Engineering Control and Imaging School of Computer Science Engineering and Mathematics Flinders University SA 5042 Australia China Ship Architecture Design and Research Institute Co. Ltd. Beijing 100024 China

ISBN: (纸本)9783642539619

In this study, the vortex-induced vibration (VIV) of a circular cylinder at the low Reynolds number of 200 is simulated by a transient coupled fluid-structure interaction numerical model using the combination of FLUENT and ANSYS platforms. Considering VIV with low reduced damping parameters, the trend of the lift coefficient, the drag coefficient and the displacement of the cylinder are analyzed under different oscillating frequencies of the cylinder. The frequency ratio α is a very important parameter, which has been intensively investigated here. The typical nonlinear phenomena of lockedin, beat and phases switch can be captured successfully. The evolution of vortex shedding from the cylinder and the trajectory of the 2 DOF case with varied frequency ratio is also discussed. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Vortex shedding

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Hydrodynamic analysis of floating marine structures based on an IBM-VOF two-phase flow model

Hydrodynamic analysis of floating marine structures based on...

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26th International Conference on Parallel Computational Fluid Dynamics, ParCFD 2013

作者： Lin, Nansheng Chen, Xiaoming Zhao, Chengbi Tang, Youhong Lin, Wei Department of Naval Architecture and Ocean Engineering School of Civil Engineering and Transportation South China University of Technology Guangdong 510641 China China Ship Architecture Design and Research Institute Co. Ltd. Beijing 100024 China Centre for Maritime Engineering Control and Imaging School of Computer Science Engineering and Mathematics Flinders University SA 5042 Australia

ISBN: (纸本)9783642539619

In this study, we develop an immersed boundary method - volume of fluid (IBM-VOF) two-phase flow solver to simulate two-phase flow problem contains solid boundaries and free surface and use it to solve the typical problems for floating marine structures. In the solver, the IBM method is adapted to solve the problems of the moving marine structures and the VOF method for solving the problems of a free surface flow. The free surface at the fluid is considered as the mixed fluid of sea water and air in the solver. Base on this IBM-VOF two-phase flow model, hydrodynamic analysis of a floating marine structure with forced heave motion is done, and hydrodynamic force coefficients are computed. In this case, we firstly calculate the forces of the floating marine structure under different frequencies, and then we get added mass and added damping through fitting the data of the forces by the least square method. The results obtained from the present model are compared, which verified the reliability and accuracy of this numerical model. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Least squares approximations

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2D systems based iterative learning control design for multiple-input multiple-output systems

2D systems based iterative learning control design for multi...

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International Conference on Methods and Models in Automation and Robotics (MMAR)

作者： Lukasz Hladowski Thanh Van Dinh Krzysztof Galkowski Eric Rogers Chris T Freeman Institute of Control and Computation Engineering University of Zielona Gora Poland Electronics and Computer Science University of Southampton UK

Iterative learning control can be applied to systems that repeat the same task over a finite duration with resetting to the starting location once each one is complete. The novel feature is the use of information from previous executions of the task in order to update the control signal applied during the next one and thereby sequentially improve performance. Linear iterative learning control laws can be designed using 2D systems theory and recently experimental validation of such designs for single-input single-output examples has been reported. This paper gives the first results on extending this approach to systems with more than one input and output.

关键词： MIMO Vectors Stability analysis Asymptotic stability State-space methods Robots Convergence

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Principal Component Analysis Anomaly Detector for Rotor Broken Bars

Principal Component Analysis Anomaly Detector for Rotor Brok...

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Annual Conference of the IEEE Industrial Electronics Society

作者： Mohammed Obaid Mustafa George Georgoulas George Nikolakopoulos Control Engineering Group Department of Computer Science Electrical and Space Engineering Lulea University of Technology Laboratory of Knowledge and Intelligent Computing (KIC) Department of Computer Engineering Technological Educational Institute of Epirus

ISBN: (纸本)9781479940318

In this article a method for the detection of broken rotor bars in asynchronous machines operating under full load is presented. Unlike most Motor Current Signature Analysis (MCSA) approaches, which operate in the frequency domain, our method operates in the time domain. The scheme is based on the use of a Principal Component Analysis (PCA) fault/anomaly detector. PCA is applied on the three stator currents to subsequently calculate the Q statistic which is employed for detecting the presence/absence of a fault. The efficiency of the proposed scheme was experimentally evaluated using different fault severity levels, ranging from 1/4 of a broken bar to three broken bars. The obtained results indicate that the method can detect the caused asymmetry with a very restricted amount of data.

关键词： Principal component analysis Rotors Bars Induction motors Detectors Stators Fault detection

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Precoding decision for full-duplex X-relay channel with Decode-and-Forward

Precoding decision for full-duplex X-relay channel with Deco...

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International Wireless Communications and Mobile Computing Conference, IWCMC

作者： Themistoklis Charalambous Ioannis Krikidis Mikael Johansson Automatic Control Lab Royal Institute of Technology (KTH) Sweden Department of Electrical and Computer Engineering University of Cyprus

In this paper, we study a simple X-relay configuration where the shared relay operates in full-duplex (FD) mode. The relay node may have limited spatial degrees of freedom, and as a result, it may not be able to handle both the loop interference and the multiuser interference. Hence, a decision on the precoding scheme is necessitated. It is often the case that the relay does not have the option of real-time switching between different precoding schemes, either due to hardware limitations of the relay or increased complexity of the problem. Hence, we investigate a “static” precoding decision where the relay node decides on its precoding scheme based only on statistical knowledge of the channel conditions. To perform this decision, the behavior of the system is formulated as a Markov chain and the outage probability of the system is derived in a closed-form with the precoding decision as a parameter. The outage probability is minimized by optimally choosing the precoding scheme, using easily verifiable conditions on the statistical knowledge of the channel conditions. Simulations validate the investigated scheme.

关键词： Relays Interference Decoding Markov processes Transmitting antennas Receiving antennas Equations

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Kinematically Optimised Predictions of Object Motion

Kinematically Optimised Predictions of Object Motion

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IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Dominik Belter Marek Kopicki Sebastian Zurek Jeremy Wyatt Institute of Control and Information Engineering Poznan University of Technology Poland School of Computer Science University of Birmingham UK

ISBN: (纸本)9781479969357

Predicting the motions of rigid objects under contacts is a necessary precursor to planning of robot manipulation of objects. On the one hand physics based rigid body simulations are used, and on the other learning approaches are being developed. The advantage of physics simulations is that because they explicitly perform collision checking they respect kinematic constraints, producing physically plausible predictions. The advantage of learning approaches is that they can capture the effects on motion of unobservable parameters such as mass distribution, and frictional coefficients, thus producing more accurate predicted trajectories. This paper shows how to bring together the advantages of both approaches to achieve learned simulators of specific objects that outperform previous learning approaches. Our approach employs a fast simplified collision checker and a learning method. The learner predicts trajectories for the object. These are optimised post prediction to minimise interpenetrations according to the collision checker. In addition we show that cleaning the training data prior to learning can also improve performance. Combining both approaches results in consistently strong prediction performance. The new simulator outperforms previous learning based approaches on a single contact push manipulation prediction task. We also present results showing that the method works for multi-contact manipulation, for which rigid body simulators are notoriously unstable.

关键词： Object motion simulator trajectory mass distribution checker physical simulation Rigid coefficient of friction Collisions

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Identification of a linear driver model based on simulator experiments

Identification of a linear driver model based on simulator e...

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International Symposium on Applied Computational Intelligence and Informatics ( SACI)

作者： András Mihály Péter Gáspár Department of Control for Transportation and Vehicle Systems Budapest University of Technology and Economics Budapest Hungary Institute for Computer Science and Control MTA-BME Control Engineering Research Group Hungary

The paper presents a driver model identification method based on simulator experiments. The visual and vestibular perception of the driver can be modeled by measuring proper signals of the vehicle motion and the environment during the real-time driving of the simulator. The parameters of different drivers are then estimated using a linear difference autoregressive model structure and least-squares estimation techniques. The aim of the identification is to describe the different driver behaviors with the parameters of a driver model with similar structure. The identified driver models are validated by simulation using the same excitation signals as in the simulator experiment and comparing the measured and simulated output of the driver. The main novelty of the paper is the identification method in which a real-time simulator is used.

关键词： Vehicles Roads Computational modeling Geometry Real-time systems Acceleration Mathematical model

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control software synthesis and validation for a vehicular electric power distribution testbed

Control software synthesis and validation for a vehicular el...

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作者： Rogersten, Robert Xu, Huan Ozay, Necmiye Topcu, Ufuk Murray, Richard M. Stockholm100 44 Sweden University of Maryland Aerospace Engineering and Institute for Systems Research College ParkMD20742 United States University of Michigan Electrical Engineering and Computer Science Ann ArborMI48109 United States University of Pennsylvania Electrical and Systems Engineering PhiladelphiaPA19104 United States California Institute of Technology Control and Dynamical Systems PasadenaCA91125 United States

Modern aircraft increasingly rely on electric power, resulting in high safety criticality and complexity in their electric power generation and distribution systems. Motivated by the resulting rapid increase in the costs and duration of the design cycles for such systems, the use of formal specification and automated correct-by-construction control protocols synthesis for primary distribution in vehicular electric power networks is investigated. A design workflow is discussed that aims to transition from the traditional "design and verify" approach to a "specify and synthesize" approach. An overview is given of a subset of the recent advances in the synthesis of reactive control protocols. These techniques are applied in the context of reconfiguration of the networks in reaction to the changes in their operating environment. These automatically synthesized control protocols are also validated on high-fidelity simulation models and on an academic-scale hardware testbed. Copyright © 2014 by Robert Rogersten, Huan Xu, Necmiye Ozay, Ufuk Topcu, and Richard M. Murray. Published by the American institute of Aeronautics and Astronautics, Inc., with permission.

关键词： Electric power distribution

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Signal-anticipating in local voltage control in distribution systems

Signal-anticipating in local voltage control in distribution...

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IEEE International Conference on Smart Grid Communications (SmartGridComm)

作者： Jeries Shihadeh Seungil You Lijun Chen Electrical Computer and Energy Engineering University of Colorado Boulder Control and Dynamical Systems California Institute of Technology Computer Science & Telecommunications University of Colorado Boulder

In this paper, we consider the signal-anticipating behavior in local volt/var control in distribution systems. We define a voltage control game, and show that the signal-anticipating voltage control is the best response algorithm of the voltage control game. We further show that the voltage control game has a unique Nash equilibrium, characterize it as the optimum of a global optimization problem, and establish its asymptotic global stability. We then introduce the notion of the price of signal-anticipating (PoSA) to characterize the impact of the signal-anticipating in local voltage control, and use the gap in cost between the network equilibrium in the signal-taking voltage control and the Nash equilibrium in the signal-anticipating voltage control as the metric for PoSA. We characterize how the PoSA scales with the size, topology, and heterogeneity of the power network for a few special cases. We find that the stronger the coupling between different buses is, the larger the PoSA is; the linear network gives the largest PoSA among all possible topologies, but as the size of the network increases, the PoSA will saturate.

关键词： Voltage control Reactive power Games Nash equilibrium Optimization Network topology Topology

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Application of a repetitive process setting to design of monotonically convergent iterative learning control

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Journal of Physics: Conference Series 2015年第1期659卷

作者： Marcin Boski Wojciech Paszke Faculty of Computer Science Electrical Engineering and Control Engineering University of Zielona Góra ul. Szafrana 2 65-516 Zielona Góra Poland Institute of Control and Computation Engineering University of Zielona Góra ul. Szafrana 2 65-516 Zielona Góra Poland

This paper deals with the problem of designing an iterative learning control algorithm for discrete linear systems using repetitive process stability theory. The resulting design produces a stabilizing output feedback controller in the time domain and a feedforward controller that guarantees monotonic convergence in the trial-to-trial domain. The results are also extended to limited frequency range design specification. New design procedure is introduced in terms of linear matrix inequality (LMI) representations, which guarantee the prescribed performances of ILC scheme. A simulation example is given to illustrate the theoretical developments.

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