一种新型非接触位姿检测系统研究

提出一种基于位置敏感探测器(简称PSD)多光束同步检测技术的位姿检测新方法,采用两个二维PSD从不同角度同时测量出目标物体上多个特征点的二维坐标,然后通过坐标变换计算得到各点的三维空间坐标;根据位姿变化前后的各点空间坐标,采用比较简单的算法计算出目标物体的位姿参数.通过算例验证该方法是可行的;由初步的实验获得目标物体的位姿参数,最大平移误差为1.0574mm,最大旋转误差为0.2851rad,需要通过多种途径进一步提高系统的检测精度.     

基于三次拟合方程畸变校正的光电测量系统

在大视场光电测量系统中,光学系统产生的畸变使目标在线阵CCD上的成像偏离了理论成像点,导致系统产生测量误差.为了减小该误差,提高系统的测量精度,根据畸变产生机理,设计了由11个等距目标点组成的畸变检测装置.根据检测得到的系统实际畸变变化情况,需要拟合出系统测量时目标点在线阵CCD上成像位置的补偿方程.以检测装置测量拟合得到的三次补偿方程作为畸变校正的数学模型编写了测量校正程序,对光电测量系统进行了实验检测.测量结果表明,当目标物物高为200.115mm时,按照拟合的补偿方程进行计算补偿,可将畸变误差从校正前的-2.08mm提高到校正后的0.05mm,并使系统整体检测精度从1.039%提高到0.025%.     

高精度动态星模拟器的光学系统设计

为了完成星敏感器的地面标定工作,满足动态星模拟器大视场、高精度的技术要求,根据动态星模拟器的工作原理,利用ZEMAX软件完成光学系统设计,实现了高精度动态星模拟器准确模拟星点。实验结果表明:系统焦距为110 mm,视场为16°,光谱范围为0.5～0.8 μm,全视场角内准直光学系统相对畸变≤0.05%,在60线对/mm时调制传递函数（MTF）优于0.7。提出了装配后确定系统实际焦面的方法,最后对光学系统实际出射精度进行分析和实验验证,验证结果表明:设计的高精度动态星模拟器光学系统的成像精度达到9″,实测的星间角距误差均优于13″,整个系统可以满足高精度动态星模拟器的使用要求。     

基于多台GoPro相机全景影像的近景摄影测量

当利用传统针孔相机进行摄影测量时,会存在视场较窄的限制。全景相机可以解决传统针孔相机视场有限的问题,使用全景影像进行摄影测量可以提高制图的效率。该文选用GoPro Hero4相机进行摄影测量,首先,对图像进行拼接,形成全景影像。其次,建立全景影像的共同投影中心、物点共线方程。再次,采用光束法平差,解算全景影像的外方位元素和物方空间坐标。最后,通过试验验证该方法的精度,在有良好控制点的条件下,该方法的测量精度高于6 cm。     

多站点近景摄影测量系统研究

本文介绍了一种多站点近景摄影测量系统,即通过使用近景摄影测量技术,在多个站点观测目标,可提高测量精度．该系统构建了一种简易控制场,采用基于共线方程式的解析处理方法,通过空间后方交会算法对系统进行标定,并通过多片空间前方交会算法解算目标的空间坐标．试验结果表明,在长宽高各3m的范围内,该系统的多个目标距离测量的平均中误差为0．07mm．     

无人机机载载荷安装位姿实时测量系统设计

主要描述了一种快速6自由度测量系统的硬件及软件设计,该测量系统能够对无人机遥测平台上机载载荷进行实时安装检测,确保所有搭载的载荷都能实时调整到预定位置上。系统基于视觉测量原理,利用固定式多目标光学靶的空间坐标将物体的空间位置姿态的变化反演出来,实现物体的6D快速测量,其中角度测量重复性为0.05°,位置测量重复性为0.05 mm。     

轮对外形轮廓检测中摄像机系统的标定算法

基于光截图像测量技术的轮对外形尺寸动态检测系统中,CCD摄像机拍摄的车轮外形图像畸变严重.本文分析了造成图像畸变和失真的原因,设计了二次、三次、四次标定模型,利用标定棋格图定性比较了各种标定模型的标定效果,确定了适合本测量系统的标定算法.针对该标定算法,定量分析了视场中心区域和视场边缘区域的校正效果,并对实际测量中获得的高速动车组车轮外形轮廓光截图像进行了校正,定性展示了校正前后的效果.现场试验表明,本文提出的标定算法取得了很好的效果,标定精度达到0.1 mm,满足轮对动态检测需要.     

一种弹丸炸点空间三维坐标测量系统

一种用来检测弹丸接近空间特定目标时作用效能的弹丸炸点空间三维坐标测量系统.文章分析已有的立靶精度测量和炸点位置测量方法,选择了测量弹丸炸点空间位置坐标的最佳组合方案,介绍利用交汇光幕立靶测量与数码影像比例算法组合的测量原理和空间坐标计算公式.     

溶质维尔德常数分离检测及其应用研究

文章基于法拉第磁光效应原理,设计了溶质维尔德常数分离检测系统.该系统可以消除溶剂和容器等背景旋光的影响,达到分离检测溶质维尔德常数的目的.系统采用了双光路参比放大信号处理技术,提高了系统的检测灵敏度.分析了系统的检测精度与误差,结果表明,检测精度与除法放大器的精度和放大倍数、标准物质及待测物质的维尔德常数有关;小角度近...     

航空变焦镜头的小型化设计

航空相机的光学系统决定相机的外形尺寸,针对一个25倍航空变焦镜头的光学设计指标要求,进行小型化设计.为缩短筒长,采用负组补偿偏离物像交换变焦结构,缩短变倍补偿系统各组元焦距,增加前固定组和变倍组间距的设计方案,通过解初级像差方程求得初始结构,依据像差理论,利用ZEMAX自动设计软件进行像差校正平衡.设计结果表明,该系统可以实现20～500 mm的连续变焦,筒长只有198 mm,中心视场传递函数值大于0.4,0.7视场传递函数值大于0.2.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...