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A reduced-order method for parameter identification of a crystal plasticity model considering crystal symmetry

Science China(Technological Sciences) 2019年第3期62卷 373-387页

作者： HAN ShiWei YANG XiaoGuang SHI DuoQi HUANG Jia School of Energy and Power Engineering Beihang University Beijing Key Laboratory of Aero-Engine Structure and Strength Shijiazhuang Flying College

The focus of this paper is to identify the material parameters of a crystal plasticity model for Ni-base single crystal superalloys.To facilitate the stepwise calibration of the multistage flow rules, further decoupling and simplification are implemented without compromising its simulating capability. reduced-order kinematics in crystal plasticity, which only comprise scalar components instead of their original tensors, are derived by considering the crystal symmetry and uniaxial loading condition. The relationships between components in elastic and plastic deformation gradient are established by explicitly accounting the control quantities, which is overall load in stress-controlled creep tests or displacement of gauge section in strain-controlled experiments,respectively. In addition, their approximate forms are also given by neglecting both elastic changes in volume and section area. A new objective function based on the shortest distance was introduced to correlate data from the simulations and experiments, and an integrated optimization process without finite element computation was developed into a commercial software package.Parameters in the crystal plasticity model are successfully calibrated by the efficient reduced-order method from the experimental data in such a sequence as: elastic, plastic, primary stage and secondary to tertiary stages creep laws. The multistage weak coupling flow rules can significantly reduce the non-uniqueness of the optimal solution under the circumstance of excessive parameters but insufficient experimental data. Finally, the optimized results with the reduced-order method have been validated by the finite element method.

关键词： reduced-order crystal plasticity parameter identification finite deformation single crystal crystal symmetry

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New LMI Conditions for reduced-order Observer of Lipschitz Discrete-time Systems: Numerical and Experimental Results

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International Journal of Automation and computing 2019年第5期16卷 644-654页

作者： Noussaiba Gasmi Assem Thabet Mohamed Aoun Research Center for Automatic Control of Nancy CRAN-CNRS UMR 7039University of LorraineCosnes et Romain 54400France Modeling Analysis and Control of Systems(MACS)LaboratoryNational Engineering School of GabesUniversity of GabesGabes 6072Tunisia

The objective of this paper is to propose a reduced-order observer for a class of Lipschitz nonlinear discrete-time systems.The conditions that guarantee the existence of this observer are presented in the form of linear matrix inequalities(LMIs). To handle the Lipschitz nonlinearities, the Lipschitz condition and the Young′s relation are adequately operated to add more degrees of freedom to the proposed LMI. Necessary and sufficient conditions for the existence of the unbiased reduced-order observer are given. An extension to H_∞ performance analysis is considered in order to deal with H_∞ asymptotic stability of the estimation error in the presence of disturbances that affect the state of the system. To highlight the effectiveness of the proposed design methodology, three numerical examples are considered. Then, high performances are shown through real time implementation using the ARDUINO MEGA 2560 device.

关键词： reduced-order observer discrete-time systems Lipschitz systems H_∞ ARDUINO MEGA 2560 device

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Non-intrusive reduced-order model for predicting transonic flow with varying geometries

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Chinese Journal of Aeronautics 2020年第2期33卷 508-519页

作者： Zhiwei SUN Chen WANG Yu ZHENG Junqiang BAI Zheng LI Qiang XIA Qiujun FU Research Institute of Unmanned Aerial Vehicle Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Space Physics Laboratory Beijing 100076China

A Non-Intrusive reduced-order Model(NIROM)based on Proper Orthogonal Decomposition(POD)has been proposed for predicting the flow fields of transonic airfoils with geometry parameters.To provide a better reduced-order subspace to approximate the real flow field,a domain decomposition method has been used to separate the hard-to-predict regions from the full field and POD has been adopted in the regions individually.An Artificial Neural Network(ANN)has replaced the Radial Basis Function(RBF)to interpolate the coefficients of the POD modes,aiming at improving the approximation accuracy of the NIROM for non-samples.When predicting the flow fields of transonic airfoils,the proposed NIROM has demonstrated a high performance.

关键词： Artificial Neural Network Domain decomposition Geometric parameters Non-Intrusive reduced-order Model Proper Orthogonal Decomposition Transonic flow

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reduced-order GPIO Based Dynamic Event-Triggered Tracking Control of a Networked One-DOF Link Manipulator Without Velocity Measurement

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 725-734页

作者： Jiankun Sun Jun Yang Shihua Li School of Automation Southeast UniversityNanjing 210096China IEEE School of Automation Southeast UniversityKey Laboratory of Measurement and Control of CSEMinistry of EducationNanjing 210096China

In networked robot manipulators that deeply integrate control, communication and computation, the controller design needs to take into consideration the limited or costly system resources and the presence of disturbances/uncertainties. To cope with these requirements, this paper proposes a novel dynamic event-triggered robust tracking control method for a onedegree of freedom(DOF) link manipulator with external disturbance and system uncertainties via a reduced-order generalized proportional-integral observer(GPIO). By only using the sampled-data position signal, a new sampled-data robust output feedback tracking controller is proposed based on a reduced-order GPIO to attenuate the undesirable influence of the external disturbance and the system uncertainties. To save the communication resources, we propose a discrete-time dynamic event-triggering mechanism(DETM), where the estimates and the control signal are transmitted and computed only when the proposed discrete-time DETM is violated. It is shown that with the proposed control method, both tracking control properties and communication properties can be significantly improved. Finally, simulation results are shown to demonstrate the feasibility and efficacy of the proposed control approach.

关键词： Dynamic event-triggering mechanism(DETM) external disturbance and system uncertainties networked robot manipulator reduced-order generalized proportional-integral observer(GPIO) robust control

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A reduced-order method for estimating the stability region of power systems with saturated controls

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Science China(Technological Sciences) 2007年第5期50卷 585-605页

作者： GAN DeQiang XIN HuanHai QIU JiaJu HAN ZhenXiang Department of Electrical Engineering Zhejiang University Hangzhou 310027 China Department of Electrical Engineering Zhejiang University Hangzhou 310027 China Department of Electrical Engineering Zhejiang University Hangzhou 310027 China Department of Electrical Engineering Zhejiang University Hangzhou 310027 China

In a modern power system, there is often large difference in the decay speeds of transients. This could lead to numerical problems such as heavy simulation burden and singularity when the traditional methods are used to estimate the stability re- gion of such a dynamic system with saturation nonlinearities. To overcome these problems, a reduced-order method, based on the singular perturbation theory, is suggested to estimate the stability region of a singular system with saturation nonlinearities. In the reduced-order method, a low-order linear dynamic system with saturation nonlinearities is constructed to estimate the stability region of the primary high-order system so that the singularity is eliminated and the estimation process is simplified. In addition, the analytical foundation of the reduction method is proven and the method is validated using a test power system with 3 buses and 5 machines.

关键词： saturation nonlinearity, power system stabilizer, linear matrix inequality, singular perturbation method, reduced-order method

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An LMI-based unified approach to reduced-order controller design

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Science China(Technological Sciences) 1997年第6期40卷 612-622页

作者：郭雷忻欣冯纯伯 Research Institute of Automation Southeast University Nanjing 210096 China

The design of reduced-order controllers is considered for stabilization control, covariance upper bound control, linear quadratic regulator, ∞ control, H∞ control, positive real control problems and robust H2 control, robust ∞ control and robust H∞ control problems for generalized linear plants without any additional assumptions. An upper bound of the order is obtained with which the (robust) controllers can guarantee stability constraints and satisfy the same design objectives as the so-called "full-order" controllers. A unified linear-matrix-inequality ( LMI) based approach to reduced-order (robust) controller design for all the above-mentioned problems is provided. It us shown that each of these problems is solvable if and only if two uncoupled LMIs with an LMI-type constraint have a pair of positive definite solutions, one of which has a lower dimension than that given by Skelton and iwasaki (1995). All desired reduced-order (robust) controllers are parameterized via the solutions of LMIs

关键词： robust control linear system matrix inequality reduced-order controller.

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A reduced-order Model for Structural Wave Control and the Concept of Degree of Controllability

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Science China Mathematics 1994年第10期37卷 1216-1222页

作者：王泉王大钧苏先樾 Department of Mechanics Peking University Beijing 100871 PRC

This paper introduces the concept and criteria of controllability and degree of controllability for structural wave control, and advances a new approach to structural reduced-order model, which is similar to the constrained substructural method in dynamics, and is also the extension of the method of aggregation raised by Aoki. It has physical meaning and is easy to realize.

关键词： reduced-order model degree of controllability wave control.

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reduced-order output feedback controllers for the robust H^(∞) performance problem

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Chinese Science Bulletin 1997年第6期42卷 517-522页

作者： GUO Lei, XIN Xin and FENG ChunboRescarch Institute of Automation, Southeast University, Nanjing 210096, China Research Institute of Automation Southeast University Nanjing China

OVER the last decade, the H~∞ control has been recognized as one of the most effective tools for robust control. A lot of researches have been devoted to robust H~∞ problems for uncertain systems. Recently, Zhou et al., presented the notion of strongly robust H~∞ performance, which is an extension of quadratic stability and equivalent to robust H~∞ problem. However. only state-feedback controllers were discussed.

关键词： robust control H∞ control matrix inequality reduced-order controller.

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Observer based projective reduced-order synchronization of different chaotic systems

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Journal of Harbin Institute of Technology(New Series) 2010年第5期17卷 697-700页

作者：李冠林陈希有刘凤春牟宪民 Dept.of Electrical Engineering Dalian University of Technology

The projective reduced-order synchronization of two different chaotic systems with different orders is investigated based on the observer design in this paper.According to the observer theory,the reduced-order observer is designed.The projective synchronization can be realized by choosing the transition matrix of the observer as a diagonal matrix.Further,the synchronization between hyperchaotic Chen system(fourth order)and Rssler system(third order)is taken as the example to demonstrate the effectiveness of the proposed observer.Numerical simulations confirm the effectiveness of the method.

关键词： chaotic systems projective synchronization observer reduced-order

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SECOND-order AGGREGATION AND EXTERNAL PARTITION reduced-order METHODS FOR POWER SYSTEMS

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Science China Mathematics 1989年第11期32卷 1364-1370页

作者：刘取张庆民黄眉 Tsinghua University Beijing 100084 PRC

This paper studies the dynamic structure property and reduced-order methods of power systems. Based on the dynamic structrue property, i.e. the mode-machlne associate property of power systems, two reduced-order methods named second-order aggregation and external system partition are presented in this paper. The first one reduces an nmachine system down to a 2n×2nth-order model which contains all the swing models. The second one reduces the system to a lower-dimension al model while all the modes associated with a portion of the system can be computed.

关键词： large power system stability reduced-order method.

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