脉冲电容器绝缘老化和直流局部放电测试系统

为研究脉冲功率系统中储能电容器的绝缘老化规律,模拟高压储能电容器实际工作过程,搭建了其电应力老化系统。基于平衡法,设计了直流局部放电脉冲测试装置和数据采集模块,得到局部放电脉冲簇。为消除单脉冲触发采集中的误触发干扰,提取单个脉冲的时频特性,基于局部放电脉冲和干扰脉冲在时频图中的不同特性,滤除干扰脉冲从而得到局部放电脉冲数据库,并利用该数据库,得到不同老化阶段的局部放电统计特性。该系统解决了直流电压下脉冲电容器现场局部放电测试的低灵敏度和干扰抑制问题,为研究短时大电流对脉冲电容器绝缘系统的破坏规律提供了基础,可用于脉冲功率系统中脉冲电容器绝缘状态和绝缘寿命的评估,剔除存在绝缘击穿危险的电容器,从而提高脉冲功率系统的稳定性。     

Experimental validation of non-contacting measurement method using LED-optical displacement sensors for vibration stress of small-bore piping

There have been many reports of fatigue failures of small-bore piping systems such as drain piping, vent piping and instrumentation piping in nuclear power plants that arise from vibration sources such as pumps. To prevent the failures, integrity evaluation of piping is conducted by measuring and analyzing vibration stress in the piping. But, a more efficient and economical measurement method is desirable to evaluate the vibration fatigue in small-bore piping. In this study, a non-contacting measurement method was proposed that is based on optical displacement sensors using light emission diodes (LEDs) to measure the vibration stress. The applicability of the method was discussed based on the vibration experiments using pipe elements and a mock-up piping system. From the experimental results, the proposed method was clarified to be sufficiently applicable and practically useful for the vibration measurement and stress evaluation in small-bore piping systems.     

基于原型的渐进式工艺设计过程理论研究

研究工艺设计过程的概念、方法和模型的工艺设计过程理论，是ＣＡＰＰ的理论基础。它对ＣＡＰＰ体系结构、开发工具、过程优化以及智能型、并行和实用型ＣＡＰＰ系统的研究与开发有着重要的影响。本文通过对人类专家设计过程的分析，揭示出工艺设计过程的一些基本特征：渐进性、并发性和层次性。提出了基于原型的渐进式工艺设计过程理论，讨论了它的应用     

A New Method of Non-Contact Measurement for Microtopography in Semiconductor Wafer Implementing a New Optical Probe Based on the Precision Defocus Measurement

In this paper, a new method of non-contact measurement has been developed for 3D topography for a semiconductor wafer, implementing a new optical probe based on precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. A distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. A precision calibration technique has been applied, giving about 10 nm resolution and 72 nm four-sigma uncertainty. In order to quantitise the micro pattern on the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and the excellent 3D measurement capability.     

利用信号拼接提高调频连续波激光测距系统的分辨力

提出了一种对等频率间隔的采样信号进行拼接来提高调频连续波激光测距系统的测距分辨力的方法。研究了调频连续波激光测距的原理,设计搭建了基于一种双干涉系统的光纤调频连续波激光测距系统。利用辅助干涉系统产生的时钟信号对测量干涉系统的信号进行等光频间隔的采样,然后对采样信号进行拼接。使用LabVIEW设计了信号错误检测处理、采样和拼接的信号处理系统。利用该测距系统进行了实验验证,结果显示,将等光频间隔的采样信号进行拼接的方法可以突破激光器扫描范围的限制,减少光源非线性的影响,从而提高系统的测距分辨力。得到结果表明,在测量距离为8.7m时,该系统的测距分辨力可达70μm,30组测量结果的重复性标准差为35μm。     

Neural robust control for perturbed crane systems

In this paper, we present a new control methodology for perturbed crane systems. Nonlinear crane systems are transformed to linear models by feedback linearization. An inverse dynamic equation is applied to compute the system PD control force. The PD control parameters are selected based on a nominal model and are therefore suboptimal for a perturbed system. To achieve the desired performance despite model perturbations, we construct a neural network auxiliary controller to compensate for modeling errors and disturbances. The overall control input is the sum of the nominal PD control and the neural auxiliary control. The neural network is iteratively trained with a perturbed system until acceptable performance is attained. We apply the proposed control scheme to 2- and 3-degree-of-freedom (D.O.F.) crane systems, with known bounds on the payload mass. The effectiveness of the control approach is numerically demonstrated through computer simulation experiments.     

Augmented nonlinear differentiator design and application to nonlinear uncertain systems

In this paper, an augmented nonlinear differentiator (AND) based on sigmoid function is developed to calculate the noise-less time derivative under noisy measurement condition. The essential philosophy of proposed AND in achieving high attenuation of noise effect is established by expanding the signal dynamics with extra state variable representing the integrated noisy measurement, then with the integral of measurement as input, the augmented differentiator is formulated to improve the estimation quality. The prominent advantages of the present differentiation technique are: (i) better noise suppression ability can be achieved without appreciable delay; (ii) the improved methodology can be readily extended to construct augmented high-order differentiator to obtain multiple derivatives. In addition, the convergence property and robustness performance against noises are investigated via singular perturbation theory and describing function method, respectively. Also, comparison with several classical differentiators is given to illustrate the superiority of AND in noise suppression. Finally, the robust control problems of nonlinear uncertain systems, including a numerical example and a mass spring system, are addressed to demonstrate the effectiveness of AND in precisely estimating the disturbance and providing the unavailable differential estimate to implement output feedback based controller.     

大气透过率的多点移动测量

考虑大气透射仪的光源不稳定性以及光学准直及大气环境的动态变化均会对其测量精度产生影响,本文在高精度导轨上设计了多点移动大气透过率测量系统,以便提高其大气透过率及消光系数的测量精度。该系统采用可移动测试平台,运用多点移动测量的方式测量大气透过率及消光系数。基于理论比较了多点移动大气透过率测量方法与传统大气透射仪测量方法的测量精度,证明了该系统的测量精度高于传统大气透射仪。将该系统与经过良好校正的Skopograph II型大气透射仪在大气环境模拟舱进行了较长时间的对比验证。结果表明,两套系统具有很好的相关性,91.93%的数据对偏差在10%以内,相关系数达0.985 7。在低能见度条件下,多点移动大气透过率测量系统的测量稳定性优于传统大气透射仪。得到的结果显示:该系统能够满足大气透过率和消光系数测量对准确性、稳定性和一致性的要求。     

基于激光三角法的圆度误差在线检测技术研究

提出了一种基于激光三角测距原理的圆度误差在线检测新方法。论述了检测系统的构成、测量原理和测量方法,讨论了主轴回转误差的分离,最后在普通车床上进行了实验验证,并用三坐标测量机作了对比测量,结果表明,两种测量方法的标准差均为0.75μm,两者间相对误差平均为4%。     

Deadlock-free scheduling of an automated manufacturing system using an enhanced colored time resource Petri-net model-based evolutionary endosymbiotic learning automata approach

Deadlock-free scheduling of parts is vital for increasing the utilization of an Automated Manufacturing System (AMS). An existing literature survey has identified the role of an effective modeling methodology for AMS in ensuring the appropriate scheduling of the parts on the available resources. In this paper, a new modeling methodology termed as Extended Color Time Net of Set of Simple Sequential Process with Resources (ECTS³PR) has been presented that efficiently handles dynamic behavior of the manufacturing system. The model is subsequently utilized to obtain a deadlock-free schedule with minimized makespan using a new Evolutionary Endosymbiotic Learning Automata (EELA) algorithm. The ECTS³PR model, which can easily handle various relations and structural interactions, proves to be very helpful in measuring and managing system performances. The novel algorithm EELA has the merits of both endosymbiotic systems and learning automata. The proposed algorithm performs better than various benchmark strategies available in the literature. Extensive experiments have been performed to examine the effectiveness of the proposed methodology, and the results obtained over different data sets of varying dimensions authenticate the performance claim. Superiority of the proposed approach has been validated by defining a new performance index termed as the ‘makespan index’ (MI), whereas the ANOVA analysis reveals the robustness of the algorithm.     

Iterative Angular Feature Extraction (IAFE) Method for Reverse Engineering

Extracting exact features from noisy point data is an important problem, in practice, for the application of reverse engineering. Several feature extraction methods have been used to handle noisy point data, such as the "angular" method and the "chordal" method. They work well for most cases, but the generation of extra features cannot be avoided for some cases. A new feature extraction method that deals with noisy scanned point data is proposed in this paper. We call it the iterative angular feature extraction (IAFE) method, since it extends the concept of the angular method. The IAFE method first distinguishes the feature regions from point clouds, then the iterative algorithm is applied to refine each feature region into ultimate feature points. A "noise dilution" concept is used to reduce the noise effect. A "multiple point" algorithm, an "angle variation" algorithm and an "iterations for convergence" algorithm are developed to implement the noise dilution concept. The IAFE(I) method for planar models and the IAFE(II) method for curved models are designed. The IAFE method demonstrated its usefulness in dealing with noisy point data.     

Feasibility of using thermal response methods for nonintrusive compressed air flow measurement

Robust, low-cost nonintrusive flow meters are of interest in many industries. In particular, a reliable nonintrusive flow measurement for the diagnosis of air leaks in compressed air systems is desirable. Measurement of the air flow due to leaks in the system ensures an accurate estimation of potential cost and energy savings. This study evaluates a novel method of using thermal responses to nonintrusively measure leakage rates in compressed air lines. The method uses heat and the resulting thermal response to calculate the flow rate inside the compressed air line. Compared to the current methods for flow measurement, this method can simplify flow measurement while decreasing the sensitivity to errors when measuring flow rates. In this study, the methodology of the proposed method is explained along with the potential advantages to the design. Two approaches are evaluated: a dynamic step response and sinusoidal frequency response. Simulated tests evaluate the feasibility of the proposed methods, followed by experiments that validate the simulation results. A clear correlation between the thermal step response and the flow rate indicate viability of the proposed method in simulation. Experimental results yielded similar results, confirming the validity of the proposed method. The results of a field test in an industrial environment demonstrate the capability of the approach to other flow rate measurement techniques.     

提高光纤传感测量精度的方法研究

采用激光干涉原理实现了微位移光纤传感测量.通过对光学系统和光电检测系统的研究,总结出提高光纤传感测量精度的方法,文中对微弱光信号的相位调制,数字解理过程,给出了低噪声设计的理论依据,电路参数的选取原则和预放级设计的一般方法.系统微位移测试精度约0.05nm.     

Large field-of-view deformation measurement for transmission tower based on close-range photogrammetry

The loading capacity of transmission towers cannot be calculated accurately only by finite element analysis (FEA) method. Traditional displacement sensors and strain gauges are not suit due to larger measuring range. In this paper, a novel system based on close-range photogrammetry technology (CPT) is proposed for tracking the 3D deformation of transmission tower during loading test. Artificial markers are pasted on the deformation area before loading. The 3D coordinates of these markers are reconstructed by using CPT methods at each stage, and the coordinate systems of different stages are registered together by means of global transformation points. The whole field 3D deformation under different load level is then obtained by tracking the homonymous markers among different stages. It is helpful for further analysis of the failure mechanism and mechanical properties of steel structures. The effectiveness of the proposed system is demonstrated by retrieving a full-scaled transmission tower deformation during loading test. A feasible solution for improving the load carrying capacity of the tested transmission tower is discussed. Evaluation experiment results indicate that the proposed method could achieve accuracy of 0.1 mm/m.     

火炮身管疵病深度测量系统

为了准确获取火炮身管疵病深度参数,提出了一种新的基于等效多基线立体成像的疵病深度测量方法,并采用单摄像机建立了疵病深度自动测量系统。首先,对摄像机采用Tsai两步法进行标校。接着,采用等效多基线立体成像法获取疵病图像。在此基础上,利用标校数据和图像的位置参数,通过疵病特征提取和疵病图像立体匹配处理,获取疵病深度图像的输出,从而得到准确的疵病深度值,实现对火炮身管疵病深度参数的精确测量。测试结果表明:该疵病测量系统得到的疵病深度测量绝对误差0.1 mm,相对误差5%,完全满足火炮身管疵病深度测量的需要,能够为火炮鉴定试验和伴装保障提供重要的技术支持。     

Errors of measuring picosecond light pulses by picosecond streak cameras

Errors of measuring time dependences of the light intensities of picosecond laser pulses by two electron-optical systems are studied. The first system is the picosecond streak camera made in Russia, and the second system, designed in Germany, consists of a picosecond streak camera coupled with a double spec-trograph. The manufacturers test similar systems by using femtosecond pulses, however, this does not allow one to predict errors of measuring picosecond pulses. Parameters that characterize just these errors are proposed and measured. Their behavior is determined, when the amplitude (energy) of the measured pulses increases, and the influence of the cross-section shape of the light beam on the measurement accuracy is studied.     

A new hybrid pattern recognition scheme for automatic discrimination of power quality disturbances

In this paper an intelligent method for automatic detection of Power Quality Disturbances (PQDs) is presented. The proposed automatic scheme is noticed to retaining informative features or eliminating redundant features simultaneously. This paper presents an effective method, for extracting features, so-called “integrated approach”, using integration of Discrete Wavelet Transform and Hyperbolic S Transform. Moreover, a new efficient feature selection method namely Orthogonal Forward Selection by incorporating Gram Schmidt procedure and forward selection is applied for selection of the best subset features. Some different classifiers are empirically compared in order to determine the best classifier. In this automatic scheme, the variable parameters of classifiers are optimized using a powerful method namely Particle Swarm Optimization. The sensitivity of the proposed method under noisy conditions has been investigated. The average rate of correct classification using the proposed hybrid scheme for automatic discrimination of PQDs in various noise conditions 99.55% is obtained.     

多支承回转窑运行轴线零应变方向键相测量法

介绍了一种回转窑运行轴线测量的新方法,该方法在回转窑简体下面两个径向应变为零的方向安装了非接触式位移传感器,对安装在简体上的键相键进行测量,由测得的位移值计算出相应截面的回转中心。该方法克服了现有测量系统高处安装系统定位困难、测量操作复杂和测量误差大的缺点,解决了回转窑运行轴线不可监测的难题,在实际应用中效果很好。     

基于多种反求方法集成的复杂结构零件测量过程规划技术

针对现阶段复杂结构零件在反求方案规划方面的不足,提出一种基于多种反求方法集成的测量过程规划技术。从功能需求出发并结合功能－结构－特征映射原理构建复杂零件的元特征解耦模型,提取元特征作为基本测量单元;进而利用模糊数学方法对元特征与测量方法之间的匹配优度进行评价,决策出单个元特征的最佳测量方法;结合方位面理论,研究了用于描述零件元特征总体分布特性的特征状态空间与描述测量方法有效范围的设备状态空间的定义方法;以设备状态空间为参照,通过特征状态空间的分解与重组,对最优测量方法相同的元特征集合进行划分,从而获得待测零件每次定位后可同时测量的元特征测量组;在此基础上,构建元特征组合测量方案综合评价模型,实现元特征测量的组合优化。对一款直列四缸汽车发动机气缸盖实施测量,并重构CAD模型。试验结果表明：该方法可有效提高复杂结构零件的逆向测量效率与质量。     

A measuring method for large antenna assembly using laser and vision guiding technology

In this paper a new conception of a measuring method is proposed to assist precision automatic assembly of large radar antenna. Different from conventional 6-DOF tracking methods, the measuring system decomposes the measurement task into several independent steps. The measuring system consists of a camera, two laser distance meters, two position sensitive detectors (PSD) and an inclination angle sensor. The camera is adopted to guide antenna position and orientation adjustment over a large space. Laser meters and PSD sensor is used to precisely measure the position and orientation of radar antenna. To improve the practicability of measuring system, a robust vision measurement method is proposed. The mathematical models and practical calibration methods for measurement are elaborated. The preliminary experimental results agree with the methods currently being used for orientation and position measurement. The measuring method provides an alternative choice for the metrology in precision assembly. By using the method proposed in this paper, the measuring system can achieve a measurement accuracy of approximately 1 mm, which meets the accuracy requirement of large radar antenna automatic assembly application. Besides, the measuring method provides an alternative solution for large scale metrology which take the environmental impact into account.