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Hierarchical parameter estimation of DFIG and drive train system in a wind turbine generator

Xueping PAN, Ping JU, Feng WU, Yuqing JIN

《机械工程前沿（英文）》 2017年第12卷第3期页码 367-376 doi: 10.1007/s11465-017-0429-y

摘要：

A new hierarchical parameter estimation method for doubly fed induction generator (DFIG) and drive train system in a wind turbine generator (WTG) is proposed in this paper. Firstly, the parameters of the DFIG and the drive train are estimated locally under different types of disturbances. Secondly, a coordination estimation method is further applied to identify the parameters of the DFIG and the drive train simultaneously with the purpose of attaining the global optimal estimation results. The main benefit of the proposed scheme is the improved estimation accuracy. Estimation results confirm the applicability of the proposed estimation technique.

关键词： wind turbine generator DFIG drive train system hierarchical parameter estimation method trajectory sensitivity technique

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一种工业过程时变参数估计新算法——修正目标函数法

张承慧

《中国工程科学》 2001年第3卷第11期页码 54-59

摘要：

针对某些工业过程控制参数高度时变的特点和LS拟合算法存在病态估计的现象，提出了一类基于修正目标函数的时变参数估计算法，并给出递推辅助变量算法。此类算法不仅具有较强的实时跟踪能力和较高的估计精度，而且能克服病态估计，摆脱了伪随机信号在工程中带来的麻烦。新算法没有增加计算量，非常适合于工程应用，仿真及实际应用结果都证明新算法是有效的。文中给出了有关新算法的定理及其证明。

关键词：参数估计计算方法 LS算法时变系统工业生产

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Estimation of load and resistance factors using the third-moment method based on the 3P-lognormal distribution

Yan-Gang ZHAO, Zhao-Hui LU

《结构与土木工程前沿（英文）》 2011年第5卷第3期页码 315-322 doi: 10.1007/s11709-011-0117-7

摘要： Load and resistance factors are generally obtained using the first order reliability method (FORM) in which the design point should be determined and derivative-based iterations used. In this article, the third-moment reliability index, based on the three-parameter lognormal (3P-lognormal) distribution, is investigated. A simple method based on the third-moment method for estimating load and resistance factors is then proposed, and a simple formula for the target mean resistance is also presented to avoid iterative computations. Unlike the currently used method, the proposed method can be used to determine load and resistance factors, even when the probability density functions (PDFs) of the basic random variables are not available. Moreover, the proposed method does not require the iterative computation of derivatives or any design points. Thus, the method provides a more convenient and effective way to estimate load and resistance factors in practical engineering applications. Numerical examples are presented to demonstrate the advantages of the proposed third moment method for determining load and resistance factors.

关键词： load and resistance factors third-moment method three-parameter lognormal (3P-lognormal) distribution target mean resistance simple formula

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基于质量感知的水下图像自适应压缩方法 Regular Papers

Ya-qiong CAI, Hai-xia ZOU, Fei YUAN

《信息与电子工程前沿（英文）》 2019年第20卷第5期页码 716-730 doi: 10.1631/FITEE.1700737

摘要：水下图像压缩是水声图像传输系统中必不可少并且至关重要的一个环节，有效的预测感知压缩图像的质量能使系统在压缩过程更好的调整压缩率，提高图像传输通信系统的效率。本文首先分别对压缩感知和嵌入式编码两种压缩策略下的水下压缩图像进行质量感知，然后利用图像活动性IAM（Image Activity Measurement）与BPP-SSIM（Bits Per Pixel and Structural SIMilarity）曲线间的映射进行建模并获得模型参数，从而根据图像的空域活动性、压缩率和压缩策略预测图像的压缩质量。实验结果表明本文所建立的模型能有效拟合水下图像的压缩质量曲线，根据模型中参数所具有的规律性能在小误差范围内预测出水下压缩图像的感知质量。本文所提出的方法能够有效的预测感知水下图像的压缩质量，并有效权衡压缩率与压缩质量之间的关系，减小发送端的数据缓存压力，提高水下图像通信系统的效率。

关键词：水下图像压缩；SPIHT压缩；压缩感知；压缩质量预测

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Structural parameter design method for a fast-steering mirror based on a closed-loop bandwidth

Guozhen CHEN, Pinkuan LIU, Han DING

《机械工程前沿（英文）》 2020年第15卷第1期页码 55-65 doi: 10.1007/s11465-019-0545-y

摘要： When a fast-steering mirror (FSM) system is designed, satisfying the performance requirements before fabrication and assembly is vital. This study proposes a structural parameter design approach for an FSM system based on the quantitative analysis of the required closed-loop bandwidth. First, the open-loop transfer function of the FSM system is derived. In accordance with the transfer function, the notch filter and proportional-integral (PI) feedback controller are designed as a closed-loop controller. The gains of the PI controller are determined by maximizing the closed-loop bandwidth while ensuring the robustness of the system. Then, the two unknown variables of rotational radius and stiffness in the open-loop transfer function are optimized, considering the bandwidth as a constraint condition. Finally, the structural parameters of the stage are determined on the basis of the optimized results of rotational radius and stiffness. Simulations are conducted to verify the theoretical analysis. A prototype of the FSM system is fabricated, and corresponding experimental tests are conducted. Experimental results indicate that the bandwidth of the proposed FSM system is 117.6 Hz, which satisfies the minimum bandwidth requirement of 100 Hz.

关键词： fast-steering mirror structural parameter PI controller bandwidth notch filter

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A novel period estimation method for X-ray pulsars based on frequency subdivision

Li-rong SHEN,Xiao-ping LI,Hai-feng SUN,Hai-yan FANG,Meng-fan XUE

《信息与电子工程前沿（英文）》 2015年第16卷第10期页码 858-870 doi: 10.1631/FITEE.1500052

摘要： Period estimation of X-ray pulsars plays an important role in X-ray pulsar based navigation (XPNAV). The fast Lomb periodogram is suitable for period estimation of X-ray pulsars, but its performance in terms of frequency resolution is limited by data length and observation time. Longer observation time or oversampling can be employed to improve frequency analysis results, but with greatly increased computational complexity and large amounts of sampling data. This greatly restricts real-time autonomous navigation based on X-ray pulsars. To resolve this issue, a new method based on frequency subdivision and the continuous Lomb periodogram (CLP) is proposed to improve precision of period estimation using short-time observation data. In the proposed method, an initial frequency is first calculated using fast Lomb periodogram. Then frequency subdivision is performed near the initial frequency to obtain frequencies with higher precision. Finally, a refined period is achieved by calculating the CLP in the obtained frequencies. Real data experiments show that when observation time is shorter than 135 s, the proposed method improves period estimation precision by 1–3 orders of magnitude compared with the fast Lomb periodogram and fast Fourier transform (FFT) methods, with only a slight increase in computational complexity. Furthermore, the proposed method performs better than efsearch (a period estimation method of HEAsoft) with lower computational complexity. The proposed method is suitable for estimating periods of X-ray pulsars and obtaining the rotation period of variable stars and other celestial bodies.

关键词： Pulsar navigation Period estimation Frequency subdivision Continuous Lomb periodogram

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Shallow foundation response variability due to soil and model parameter uncertainty

Prishati RAYCHOWDHURY,Sumit JINDAL

《结构与土木工程前沿（英文）》 2014年第8卷第3期页码 237-251 doi: 10.1007/s11709-014-0242-1

摘要： Geotechnical uncertainties may play crucial role in response prediction of a structure with substantial soil-foundation-structure-interaction (SFSI) effects. Since the behavior of a soil-foundation system may significantly alter the response of the structure supported by it, and consequently several design decisions, it is extremely important to identify and characterize the relevant parameters. Moreover, the modeling approach and the parameters required for the modeling are also critically important for the response prediction. The present work intends to investigate the effect of soil and model parameter uncertainty on the response of shallow foundation-structure systems resting on dry dense sand. The SFSI is modeled using a beam-on-nonlinear-winkler-foundation (BNWF) concept, where soil beneath the foundation is assumed to be an assembly of discrete, nonlinear elements composed of springs, dashpots and gap elements. The sensitivity of both soil and model input parameters on shallow foundation responses are investigated using first-order second-moment (FOSM) analysis and Monte Carlo simulation through Latin hypercube sampling technique. It has been observed that the degree of accuracy in predicting the responses of the shallow foundation is highly sensitive soil parameters, such as friction angle, Poisson’s ratio and shear modulus, rather than model parameters, such as stiffness intensity ratio and spring spacing; indicating the importance of proper characterization of soil parameters for reliable soil-foundation response analysis.

关键词： shallow foun dation sensitivity analysis centrifuge data first-order-second-moment (FOSM) method parameter uncertainty

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适于低成本嵌入式硬件的2R-1C模型非迭代参数估计 Article

Mitar SIMIĆ, Zdenka BABIĆ, Vladimir RISOJEVIĆ, Goran M. STOJANOVIĆ

《信息与电子工程前沿（英文）》 2020年第21卷第3期页码 476-490 doi: 10.1631/FITEE.1900112

摘要： 2R-1C模型的参数估计常运用需要高性能处理单元的迭代方法，从而激励我们研究更省时且更节能的参数估计方法。这些低复杂度的算法将更适于便携式微机设备的运行。本文提出二次插值非迭代参数估计方法（QINIPE）；该方法基于测量阻抗虚部的二次插值，能够更精确地估计特征频率。运用一组封闭表达式从测量阻抗的实部和虚部计算2R-1C模型的参数。对仿真和测量获得的模型阻抗数据作对比分析；结果表明，相较于我们早前提出的非迭代参数估计方法（NIPE），QINIPE能减少80%测量点，且所有估计参数的相对估计误差低于1%。两种非迭代方法均基于一个微机设备实施；检测了估计精度、RAM、闪存使用以及运行时间。实验结果表明，相较于NIPE，QINIPE轻微增加了0.576 ms运行时间（约6.7%），且需要多24%（1.2 KB）闪存及多2.4%（32字节）RAM。然而，QINIPE的阻抗均方根误差分别降低至NIPE对应的42.8%（实部）和64.5%（虚部）。此外，比较了QINIPE和复杂非线性最小二乘法（CNLS）对2R-1C模型参数的估计。结果表明，虽然QINIPE估计精度稍低于CNLS，其依然适合许多实际应用，且运行时间降至原来的1/45至1/30。

关键词： 2R-1C模型；嵌入式系统；参数估计；非迭代方法；二次型

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A model reference adaptive control based method for actuator delay estimation in real-time testing

Cheng CHEN, James M. RICLES

《结构与土木工程前沿（英文）》 2010年第4卷第3期页码 277-286 doi: 10.1007/s11709-010-0072-8

摘要： Real-time testing provides a viable experimental technique to evaluate the performance of structural systems subjected to dynamic loading. Servo-hydraulic actuators are often utilized to apply calculated displacements from an integration algorithm to the experimental structures in a real-time manner. The compensation of actuator delay is therefore critical to achieve stable and reliable experimental results. The advances in compensation methods based on adaptive control theory enable researchers to accommodate variable actuator delay and achieve good actuator control for real-time tests. However, these adaptive methods all require time duration for actuator delay adaptation. Experiments show that a good actuator delay estimate can help optimize the performance of the adaptive compensation methods. The rate of adaptation also requires that a good actuator delay estimate be acquired especially for the tests where the peak structural response might occur at the beginning of the tests. This paper presents a model reference adaptive control based method to identify the parameter of a simplified discrete model for servo-hydraulic dynamics and the resulting compensation method. Simulations are conducted using both numerical analysis and experimental results to evaluate the effectiveness of the proposed estimation method.

关键词： real-time testing actuator delay compensation adaptive control MIT rule discrete transfer function

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一种针对测试误差、参数误差和负荷突变故障分析的多功能动态状态估计器 Article

Mehdi AHMADI JIRDEHI,Reza HEMMATI,Vahid ABBASI,Hedayat SABOORI

《信息与电子工程前沿（英文）》 2016年第17卷第11期页码 1218-1227 doi: 10.1631/FITEE.1500301

摘要：本文提出了一种基于卡尔曼滤波理论的动态状态估计新算法，可有效探测、识别并校正电力系统中的测试误差和支路参数误差。同时，该算法亦可成功探测和识别电力系统中的负荷突变。该方法在每段取样时间内，采用三种归一化向量对误差进行处理，包括归一化测量残差，归一化拉格朗日乘子，以及归一化新息向量。在IEEE14节点测试系统上对所提出的算法进行了可行性和效能验证，并通过对数值结果的呈示和讨论，说明了该方法的精确度。

关键词：动态状态估计器；卡尔曼滤波；测试误差；支路参数误差；负荷突变

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采用线性和非线性拟合方法进行指数模型参数估计 Article

Ping YANG,Chao-peng WU,Yi-lu GUO,Hong-bo LIU,Hui HUANG,Hang-zhou WANG,Shu-yue ZHAN,Bang-yi TAO,Quan-quan MU,Qiang WANG,Hong SONG

《信息与电子工程前沿（英文）》 2017年第18卷第3期页码 434-444 doi: 10.1631/FITEE.1601683

摘要：本文探讨了通过线性和非线性拟合方法估计指数模型中的未知参数。基于多元函数极值定理及泰勒级数展开，从理论上证明了：在实验测量数据中包含噪声的情况下，通过线性拟合方法所得到的参数估计值并不能保证指数模型的残差平方和达到最小。通过数值仿真对线性和非线性拟合方法的结果进行了对比，仿真结果显示：线性方法只能获得未知参数的次优估计，但非线性方法给出更准确的结果。利用水下图像和成像距离数据对水体光谱衰减系数进行了估计，结果证实非线性拟合方法能够对参数估计准确度有明显的提升。

关键词：指数模型；参数估计；线性最小二乘法；非线性拟合

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Optimal Method of Capacitated Lot-Sizing Planning in Manufacturing Systems

CHANG Jian-feng, ZHONG Yue-xian, HAN Zan-dong

《机械工程前沿（英文）》 2006年第1卷第1期页码 67-70 doi: 10.1007/s11465-005-0020-9

摘要：

This paper analyzes the capacitated lot-sizing problem considering an individual machine s production capacity using a two-layer hierarchical method to minimize the sum of the dynamic inventory cost and the overtime penalty cost. The genetic algorithm, the parameter linear programming method, and a heuristic method were used in the developed method. The method uses the genetic operator to define the lot-sizing matrix (the first layer), linear programming to determine eachmachine' s schedule (the second layer) according to the lot-sizing matrix, and the heuristic method to verify the feasibility of the solutions by adjusting them to meet the constraint requirements. The scheduling of machines in a press shop demonstrates the effectiveness of the algorithm. The result shows that the algorithm is convergent.

关键词： heuristic two-layer hierarchical algorithm constraint developed

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基于层次的K-means初始化算法

汤九斌,陆建峰,唐振民,杨静宇

《中国工程科学》 2007年第9卷第11期页码 74-79

摘要：

K-means算法是一种常用的聚类算法，但是聚类中心的初始化是其中的一个难点。笔者提出了一个基于层次思想的初始化方法。一般聚类问题均可看作加权聚类，通过层层抽样减少数据量，然后采用自顶向下的方式，从抽样结束层到原始数据层，每层都进行聚类，其中每层初始聚类中心均通过对上层聚类中心进行换算得到，重复该过程直到原始数据层，可得原始数据层的初始聚类中心。模拟数据和真实数据的实验结果均显示基于层次抽样初始化的K-means算法不仅收敛速度快、聚类质量高，而且对噪声不敏感，其性能明显优于现有的相关算法。

关键词：层次技术初始聚类中心加权数据 K平均聚类

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Semi-analytical approach for free vibration analysis of cracked beams resting on two-parameter elastic

null

《机械工程前沿（英文）》 2014年第9卷第2期页码 191-202 doi: 10.1007/s11465-014-0293-y

摘要：

In present study, free vibration of cracked beams resting on two-parameter elastic foundation with elastically restrained ends is considered. Euler-Bernoulli beam hypothesis has been applied and translational and rotational elastic springs in each end considered as support. The crack is modeled as a mass-less rotational spring which divides beam into two segments. After governing the equations of motion, the differential transform method (DTM) has been served to determine dimensionless frequencies and normalized mode shapes. DTM is a semi-analytical approach based on Taylor expansion series that converts differential equations to recursive algebraic equations. The DTM results for the natural frequencies in special cases are in very good agreement with results reported by well-known references. Also, the DTM procedure yields rapid convergence beside high accuracy without any frequency missing. Comprehensive studies to analyze the effects of crack location, crack severity, parameters of elastic foundation and boundary conditions on dimensionless frequencies as well as effects of elastic boundary conditions on cracked beams mode shapes are carried out and some problems handled for first time in this paper. Since this paper deals with general problem, the derived formulation has capability for analyzing free vibration of cracked beam with every boundary condition.

关键词： free vibration cracked beam elastic foundation restrained ends differential transform method

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A block zero-padding method based on DCFT for L1 parameter estimations in weak signal and high dynamic

Chao WU,Lu-ping XU,Hua ZHANG,Wen-bo ZHAO

《信息与电子工程前沿（英文）》 2015年第16卷第9期页码 796-804 doi: 10.1631/FITEE.1500058

摘要： Weak L1 signal acquisition in a high dynamic environment primarily faces a challenge: the integration peak is negatively influenced by the possible bit sign reversal every 20 ms and the frequency error. The block accumulating semi-coherent integration of correlations (BASIC) is a state-of-the-art method, but calculating the inter-block conjugate products restricts BASIC in a low signal-to-noise ratio (SNR) acquisition. We propose a block zero-padding method based on a discrete chirp-Fourier transform (DCFT) for parameter estimations in weak signal and high dynamic environments. Compared with the conventional receiver architecture that uses closed-loop acquisition and tracking, it is more suitable for open-loop acquisition. The proposed method combines DCFT and block zero-padding. In this way, the post-correlation signal is coherently post-integrated with the bit sequence stripped off, and the high dynamic parameters are precisely estimated using the threshold set based on a false alarm probability. In addition, the detection performance of the proposed method is analyzed. Simulation results show that compared with the BASIC method, the proposed method can precisely detect the high dynamic parameters in lower SNR when the length of the received signal is fixed.

关键词： Threshold detection Discrete chirp-Fourier transform Block zero-padding High dynamic Weak L1 signal acquisition