用于燃气轮机动态间隙检测的光纤测量系统(II):实验与应用研究

建立了一种利用光纤测量技术实现燃气轮机动态间隙检测的实验系统，详细描述了系统的构成。实验结果表明，该实验系统能够实现对燃气轮机内部环境恶劣、高温、转速高达10000转／min的叶顶间隙的测量，所得到的数据重复性好。规律一致，说明该光纤测量系统有足够的精度，在燃气轮机、汽轮机等旋转机械的动态间隙监测领域有着广泛的应用前景。     

DDEUDSC: A Dynamic Distance Estimation using Uncertain Data Stream Clustering in mobile wireless sensor networks

In RSSI (Received Signal Strength Indicator)-based communication distance estimation of mobile wireless sensor network localization, RSSI is assumed to exponential attenuation with increment of communication distance in ideal radio propagation models, which is invalid due to the uncertainty of RSSI data in real communication environment, resulting in considerable error of communication distance estimation. Moreover, dynamic distance estimation demands a high efficiency of computation for the continual generation of RSSI data stream in the mobile node. This paper develops a new dynamic communication distance estimation method using uncertain interval data stream clustering, named as DDEUDSC (Dynamic Distance Estimation method using Uncertain Data Stream Clustering). First, statistical information of RSSI data is used to represent the RSSI-D mapping relationship in terms of interval data. Then we consider the data pattern composed of some consecutive cluster centers, and apply it in our uncertain RSSI data stream clustering algorithm to estimate the dynamic communication distance. Finally, RSSI data streams in three typical communication environments are conducted for experiments. The experimental results show the proposed method is an effective way to improve RSSI-D estimation precision in RSSI data stream with uncertainty and dynamics characteristic.     

Technique for the measurement of spatial vorticity distributions

A method for measuring mean spatial vorticity content has been described for flows where the primary convective velocity (free stream) is larger than the mean crossflow components. Employing an 'X'-geometry hot-wire probe and linearized anemometer system in conjunction with a precision probe traversing mechanism, this relatively simple technique can be used to evaluate the circulation associated with various spatial contours. Errors associated with the technique are computed exactly and in simple linearized forms to illustrate its validity in a wide range of flows. A priori knowledge of the flow character and resultant careful selection of the integration paths for a given flow situation is observed to result in minimal measurement errors. Application to the problem of an isolated trailing vortex is presented as an example. Experiments at the trailing edge of a lifting wing confirm the accuracy of the method when compared with existing theories and other experimental data. The method can be extended to periodically driven unsteady flows using phase-lock techniques.     

Numerical simulation of the flow around two circular airfoils positioned across the stream using the LS-STAG method

The flow around two circular airfoils positioned side by side (across the stream) at different distances between the airfoils is considered. The LS-STAG method, which belongs to the class of immersed boundary method is used for numerical simulation that makes it possible to calculate using rather coarse meshes. Stationary and trigger flow regimes have been simulated, as well as the patterns of flow with synchronization of two vortex trails in-phase and in anti-phase. For each regime, the typical dependences of coefficients of drag force and lift force on the time are presented. The obtained results are in good agreement with the known experimental and computational data.     

以CAPP为桥梁的PDM与ERP集成的研究

提出了以CAPP为桥梁的PDM与ERP集成的方法,并给出了以装配工艺为基础的CAPP系统的总体模型和框架。阐述了集成PDM／ERP的过程链和数据流,以及集成过程中冗余数据的控制。     

基于CH372数据采集设备的WinCE驱动设计

CH372是一种简单、易用的USB总线接口芯片,已在数据采集系统中得到广泛应用,由于没有WinCE下的驱动程序,给应用开发带来了一定的困难.文中提出了WinCE下此类USB设备驱动程序的一种设计方法,阐述了WinCE流接口驱动模型、USB流接口驱动程序的设计和CH372设备驱动程序的实现细节,并重点描述了驱动程序的入口点函数的功能与代码实现,最后分析了驱动程序的加载调用过程.通过在ARM9平台上测试表明:该驱动运行稳定,完全可以移植到具体的嵌入式产品中.     

主成分分析方法在轿车装配尺寸偏差中的应用研究

在分析轿车车体装配过程误差的基础上，根据车体制造从零件到白车身的装配过程知识，建立了白车身装配过程的树结构，并应用主成分分析方法从大量的CMM测量数据中将零件偏差分离为相互独立的几何偏差模式。针对整车总装过程中出现后桥装配干涉的实际案例，利用CMM测量和传统样架检测，运用主成分分析方法对与案例相关零部件的CMM测量数据进行了统计分析与处理，最终实现了对后桥装配干涉案例的误差源诊断，结果表明在冲压过程形成的零件偏差将保留于下游的装配过程中。     

Improved Bi-Criterion flexible registration for fixtureless inspection of compliant parts

Because of the effects of gravity and/or residual stress, some manufactured mechanical parts, such as sheet metals and skins, often have a significantly different shape in a free-state position as compared to their state-of-use position. These parts are described as compliant, flexible or nonrigid. Expensive specialized fixtures are currently used prior to performing geometrical inspection operations in order to maintain compliant parts in the state-of-use position. This paper introduces an automatic bi-criterion flexible registration method for the dimensional and geometric inspection of such parts. The proposed method deforms the data acquired via a non-contact scanner of a compliant part in a free-state position until it reaches the nominal CAD shape for inspection with conventional Computer-Aided Inspection (CAI) tools. In other words, the method neutralizes the deviations induced in a compliant part by the effects of gravity and residual stress, allowing the acquired data to be treated as if it were obtained from a rigid part, using already available conventional (rigid) CAI tools. A proposed algorithm based on the BOFR-2 (the 2nd version of a Bi-Objective Flexible Registration algorithm) method is validated against both virtual simulated and experimental real industrial case studies from the aerospace sector. The resulting cost reduction and agility increasing make this fixtureless method well adapted to the requirements of unit-batch production in the context of Industry 4.0.     

Creating an automated chiller fault detection and diagnostics tool using a data fault library

Reliable, automated detection and diagnosis of abnormal behavior within vapor compression refrigeration cycle (VCRC) equipment is extremely desirable for equipment owners and operators. The specific type of VCRC equipment studied in this paper is a 70-ton helical rotary, air-cooled chiller. The fault detection and diagnostic (FDD) tool developed as part of this research analyzes chiller operating data and detects faults through recognizing trends or patterns existing within the data. The FDD method incorporates a neural network (NN) classifier to infer the current state given a vector of observables. Therefore the FDD method relies upon the availability of normal and fault empirical data for training purposes and therefore a fault library of empirical data is assembled. This paper presents procedures for conducting sophisticated fault experiments on chillers that simulate air-cooled condenser, refrigerant, and oil related faults. The experimental processes described here are not well documented in literature and therefore will provide the interested reader with a useful guide. In addition, the authors provide evidence, based on both thermodynamics and empirical data analysis, that chiller performance is significantly degraded during fault operation. The chiller's performance degradation is successfully detected and classified by the NN FDD classifier as discussed in the paper's final section.     

An approach to carbon loss in steel during conventional chemical vapour deposition

A quantitative method is proposed to determine the amount of carbon taken from a steel substrate on forming a carbide coating when carbon is also supplied in the gas stream. Two series of experiments are necessary: one without carbon in the gas stream in order to determine the system constant and a second with carbon in the gas stream to determine the loss from the substrate. A limited number of experimental results taken from the literature show that the approach is viable. The assumptions made are reviewed and some recommendations on experimental procedure are made.     

Research on real time feature extraction method for complex manufacturing big data

Big data related to manufacturing applications has the traits such as great quantity, multi-sources, low value density, high complexity, and dynamic state. Traditional feature extraction methods are incapable of meeting real-time demands. Therefore, a robust incremental on-line feature extraction method based on PCA (Principal Component Analysis), RIPCA (Robust Incremental Principal Component Analysis), is proposed. RIPCA adopts a sliding window to update new coming data stream and to filter outliers. The proposed method could ensure the accuracy of data analysis and meet real-time demands of big data processing for manufacturing applications. A test data set based on a semiconductor manufacturing process containing 1567 records with 590 features is used to demonstrate the availability of the proposed method. Experimental results show that the method can effectively extract features of the data stream in real time with high accuracy.     

基于品质物料清单的全面质量数字化管理模式的研究

针对全面质量管理缺乏有效实施手段的现状，构建了面向企业运作过程中所有质量活动的品质物料清单体系，分析了该体系的构成、特性、作用和必要性，并采用语义化建模技术和工程化方法，描述了品质物料清单体系各成员间的关系及其数据关系模型，最终以品质物料清单体系作为合理有效的质量数据组织形式，以确保准确的质量数据统计分析，进而实现“以数据说话”的全面质量数字化管理。     

Effect of lubrication on the stress distribution in an extruded material

The visioplasticity method is used to find the complete strain, strain rate and stress distribution in the deformation zone, according to the deformation grid lines marked on the surface of the workpiece. From the experimental data (the values of the flow function for the extrusion), the velocity, strain rate and stress fields can be calculated by the finite-difference method from the stream function, equilibrium and plasticity equations. In this article, stress components distribution in forward extruded specimens of copper alloy are analysed using the visioplasticity method. Comparisons are made between stress distribution of the specimens extruded with three different coefficients of friction. The results are shown in the form of diagrams.     

多点成形件检测中三维数据配准方法的研究

针对多点成形件成形误差检测中的三维数据配准问题，提出了一种用两步法将CAD模型数据和三维测量数据点全局配准的方法。利用遗传算法具有全局搜索能力的特点，以四元数法中的3个参量作为优化解空间，采用自适应控制优化参数的方法，达到CAD模型数据和三维测量数据点的全局粗配准。以粗配准的结果作为初始值，用ICP算法修正误差以达到精确配准。采用两步法配准克服了标准ICP算法难以解决的局部最小问题，本算法也可广泛应用于精密测量时测量结果的比较分析。以马鞍形曲面制品为例，给出了配准结果。     

基于互联网的通用远程校准平台

提出一种基于互联网的通用远程校准平台,给出此类平台的设计原则.借助物流将传递单元发送到客户现场,通过互联网与校准实验室主机通信,实现远程校准.核心部分为互联网模块,能够连接标准仪器与互联网,传输指令、数据和音/视频.借助图像字符识别技术获取被校仪器数据,从而摆脱物理接口和特定仪器指令集的束缚,最大程度地实现了平台的通用性.校准不确定度取决于时间同步准确度和字符识别的正确率.采用平方同步算法与GPS时钟同步,修正后计时准确度达到亚微秒量级.提出以边缘分布函数作为图像字符的特征函数,并采用成熟的BP神经元网络作为分类器,将识别错误率降到最低.     

在线近红外用于蒸汽裂解装置石脑油进料关键性质检测

本文介绍了在线近红外用于蒸汽裂解装置石脑油进料几种关键性质的在线检测,结果表明在线近红外光谱法对石脑油50%馏程温度、70%馏程温度、环烷烃含量和异构烷烃含量的分析结果能够完全满足生产中的精度要求。该方法除有测量速度快的优点之外,还具有分析成本低、无污染、维护方便等特点,在所建立模型的预测范围内,能对样品进行准确、经济的分析。     

Wheel alignment inspection by 3D point cloud monitoring

Today’s wheel alignment inspection systems adopt various computer vision technologies. They, however, require high-end cameras, precisely manufactured targets, and massive calculation loops because they rely on low-dimensional data (two-dimensional images) for measuring higher-dimensional information (three-dimensional orientation) of the wheel posture. To improve this, a simple and inexpensive method using a consumer-grade depth-sensing camera such as Kinect is presented. It directly utilizes point clouds generated from its range image stream. All points within the region of interest (ROI) contain geometrical information of the wheel and are used for the alignment inspection procedures. Its feasibility is evaluated by examining whether the orientation could be aligned to the desired orientation using only the point cloud data. For verification, a one-wheel-based prototype was implemented, and comparative experiments with an existing commercial system were conducted. The experimental results showed that the proposed method provides satisfactory performance. We believe that the proposed method is feasible for practical usage and has a great potential to be an effective alternative to existing wheel alignment inspection methods.     

半固态材料触变成形通用本构方程及其优化

采用半固态成形机理分析和试验研究相结合的方法,建立半固态触变成形的粘塑性本构方程,并提出本构方程的优化新方法。通过半固态Al-4Cu-Mg合金的等温压缩试验研究,分析试验数据,得到本构方程中的4个待定系数,并以此作为优化设计的初试值。结合本构方程的形式,对其进行特性分析和优化。将含优化变量的本构方程作为子程序引入到有限元数值模拟中,可以得到对照热模拟试验结果的若干工艺条件下半固态Al-4Cu-Mg合金的应力应变曲线。通过比较有限元数值模拟结果和热模拟试验结果可知,利用提出的本构方程优化新方法,不仅可以剔除热模拟试验数据中几何效应的影响,而且还能准确地描述半固态材料的触变成形规律,从而可以提高数值模拟的精度与可靠性。     

亚音速轴流压气机转子子午流面上的流场模拟

以具有试验数据的某亚音速轴流压气机转子为研究对象,建立了子午流面上的流场模型,采用有限差分法求解转子子午流面的控制方程.计算结果与试验数据进行了对比,比较的结果说明模拟的结果能够满足工程应用的需要,并且从气流参数分布规律的角度对转子设计的合理性进行了分析.     

基于Access的热切割机数控系统数据库设计

热切割机数控系统在加工过程中需要处理大量数据,为提高数据流操作的稳定性与高效性,提出了将Access数据库技术应用到数控系统数据存储中的一种方法。分析了热切割加工工艺参数及加工代码格式,设计了相应数据库字段,构建了热切割加工工艺参数表、加工程序表以及割缝补偿表,进而构建了热切割数控系统数据库,进行了数控系统数据库读写实验。实验结果表明,数据库读写性能稳定、效率高,满足热切割数控系统的加工要求。