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parameter design for a vibration absorber with time-delayed feedback control

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Acta Mechanica Sinica 2019年第3期35卷 624-640页

作者： Feng Wang Jian Xu School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

Traditional passive vibration absorbers are effective only when their natural frequencies are close to those of the excitations. To solve this problem, a vibration absorber with time-delayed feedback control is proposed to suppress vibration of the primary system under excitation with changing frequency. Firstly, the mechanical model of the delay coupled system is established. Then, the displacement transfer ratio of the system is obtained. The stability of the system is analyzed since delay may result in destabilization. Next, in order to design the control parameters, the vibration absorption performances of the proposed time-delayed vibration absorber are studied. The vibration absorption region is shown. The results show that time-delayed feedback control is able to change the response of the system. The effective vibration absorption frequency band is adjustable by tuning the control gain and time delay. The effective frequency band can be widened when choosing appropriate control parameters. The vibration absorption performances can be greatly improved by the time-delayed absorber. In addition, the optimum control parameters are obtained. Finally, the experimental prototype is constructed. Several tests with different control parameters are taken. The experimental and analytical results match quite well.

关键词： Vibration absorber Time-delayed feedback control Vibration absorption Experiments parameter design

parameter identification and state-of-charge estimation approach for enhanced lithium–ion battery equivalent circuit model considering influence of ambient temperatures

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Chinese Physics B 2019年第10期28卷 562-570页

作者： Hui Pang Lian-Jing Mou Long Guo School of Mechanical and Precision Instrument Engineering Xi’an University of Technology

It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model(ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium-ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter(EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization(HPPC) and the standard US06 driving cycles(US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.

关键词： lithium-ion battery parameter identification state of charge ambient temperature

parameter Processes of a Strong Laser in Partially Stripped Plasmas

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Chinese Physics Letters 2000年第12期17卷 893-895页

作者： HU Xi-Wei Department of Modern Physics University of Science and Technology of ChinaHefei 230026

The effects of the nonlinear polarization in a partially stripped plasma on the parameter processes of a strong laser are discussed. The nonlinear mode coupling equations of stimulated Raman scattering (SRS) are derived. The linear instability growth rates of SRS and stimulated Brillouin scattering (SBS) are given. When the pump wave intensity I0 > 1017 W/cm2, the third order susceptibility associated with bound electrons will reduce the SRS and SBS linear growth rate enormous1y. In addition, the nonlinear susceptibility can affect the nonlinear evolution of SRS and SBS significantly.

关键词： nonlinear susceptibility parameter

parameter Optimisation of Stress-strain Constitutive Equations Using Genetic Algorithms

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Journal of Materials Science & Technology 2003年第z1期19卷 5-8页

作者： Y. Y. Yang M. Mahfouf D.A.Linkens Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK Department of Automatic Control and Systems Engineering University of Sheffield Mappin St. Sheffield S1 3JD UK

The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rollingtorque, etc., depends on the description of stress-strain relationship of the deformed materials. One common methodof describing the stress-strain relationship is using constitutive equations, with the unknown parameters fitted byexperimental data obtained via plane strain compression (PSC). Due to the highly nonlinear behaviour of the constitutive equations and the noise included in the PSC data, determination of the model parameters is difficult. Inthis paper, genetic algorithms were exploited to optimise parameters for the constitutive equations based on thePSC data. The original PSC data were processed to generate the stress-strain data, and data pre-processing wascarried out to remove the noise contained in the original PSC data. Several genetic optimisation schemes have beeninvestigated, with different coding schemes and different genetic operators for selection, crossover and *** was found that the real value coded genetic algorithms converged much faster and were more efficient for theparameter optimisation problem.

关键词： Genetic algorithms, parameter optimisa tion, Aluminium alloy, Flow stress, Constitutive equations

parameter-Free Shifted Laplacian Reconstruction for Multiple Kernel Clustering

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1072-1074页

作者： Xi Wu Zhenwen Ren F.Richard Yu the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010China the School of National Defence Science and Technology Southwest University of Science and TechnologyMianyang 621010 the Guangxi Key Laboratory of Machine Vision and Intelligent Control Wuzhou UniversityWuzhou 543002 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(SZ) Shenzhen 518060China

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MKC)method by using shifted Laplacian *** MKC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

关键词： parameter letter parameter

parameter Estimation Based on Set-valued Signals:Theory and Application

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Acta Mathematicae Applicatae Sinica 2019年第2期35卷 255-263页

作者： Ting WANG Hang ZHANG Yan-long ZHAO The Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of Sciences

This paper summarizes the parameter estimation of systems with set-valued signals, which can be classified to three catalogs: one-time completed algorithms, iterative methods and recursive algorithms. For one-time completed algorithms, empirical measure method is one of the earliest methods to estimate parameters by using set-valued signals, which has been applied to the adaptive tracking of periodic target signals. The iterative methods seek numerical solutions of the maximum likelihood estimation, which have been applied to both complex diseases diagnosis and radar target recognition. The recursive algorithms are constructed via stochastic approximation and stochastic gradient methods, which have been applied to adaptive tracking of non-periodic signals.

关键词： set-valued signals parameter estimation one-time completed algorithms iterative estimation algorithms recursive estimation algorithms

parameter identification and synchronization of spatiotemporal chaos in an uncertain Gray-Scott system

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1638-1646页

作者： LüLing LI Yi GUO ZhiAn College of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029China Department of Mathematics and Physics Dalian Jiaotong UniversityDalian 116028China

The zero-asymptotic property of sliding variables in discrete systems is extended to a continuous one and applied to partial differential equations which describe spatiotemporal chaos. A method of chaos synchronization and parameter identifi-cation is proposed. The synchronization controllers and the parameter recognizers are designed. The uncertain Gray-Scott system is taken as an example to verify the effectiveness of the method. Simulation results show that the identification vari-ables in the parameter recognizers may take the place of the unknown parameters in both target and response systems. Global synchronization of the two spatio-temporal chaotic systems with uncertain parameters may be realized quickly after controllers are added.

关键词： spatiotemporal chaos sliding variable parameter identification synchronization uncertain Gray-Scott system

parameter transferability across spatial resolutions in urban hydrological modelling:a case study in Beijing,China

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Frontiers of Earth Science 2019年第1期13卷 18-32页

作者： Xiaoshu HOU Lei CHEN Xiang LIU Miao LI Zhenyao SHEN State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China School of Environment Tsinghua UniversityBeijing 100084China

This study examined the influence of spatial resolution on model parameterization,output,and the parameter transferability between different resolutions using the Storm Water Management ***-resolution models,in which most subcatchrnents were homogeneous,and high-resolution-based low-resolution models (in 3 scenarios)were constructed for a highly urbanized catchment in *** results indicated that the parameterization and simulation results were affected by both spatial resolution and rainfall *** simulated peak inflow and total runoff volume were sensitive to the spatial resolution,but did not show a consistent ***-resolution models performed very well for both calibration and validation events in terms of three indexes:1)the Nash-Sutcliffe efficiency, 2)the peak flow error,and 3)the volume error;indication of the advantage of using these *** parameters obtained from high-resolution models could be directly used in the low-resolution models and performed well in the simulation of heavy rain and torrential rain and in the study area where sub-area routing is ***,sub-area routing should be considered and estimated *** successful scale conversion from high spatial resolution to low spatial resolution is of great significance for the hydrological simulation of ungauged large areas.

关键词： SWMM high resolution low resolution rainfall characteristics parameter transferability

parameter identification theory of a complex model based on global optimization method

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3 1 College of Automotive Engineering, South China University of Technology, Guangzhou 510640, China 2 Beijing Research Institute of Mechanical and Electrical Technology, Beijing 100083, China 3 Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China College of Automotive Engineering South China University of Technology Guangzhou China Beijing Research Institute of Mechanical and Electrical Technology Beijing China Department of Engineering Mechanics Tsinghua University Beijing China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization