采用比例谐振控制器的逆变器

逆变器的核心是控制器算法。采用比例谐振（PR）控制算法的逆变器,它的跟踪曲线比传统的采用PI控制算法的逆变器好。通过PR控制算法可以选择性地使某一频率增强,从而达到谐波过滤的效果。     

Calculation of film thickness for variable velocity

The thickness of the film between heavy loaded rollers can be calculated by an equation of Dowson and Higginson for constant velocity. For variable velocity the film thickness can be calculated approximately by an iteration. The variation of the film thicknesses can be computed by this method if pairs of consecutive values of velocity and time are given. The minimum film thickness can be calculated directly if a theoretical variation of velocity with constant acceleration is assumed.     

CNC系统加工复杂空间曲线的编程处理

采用等间隔直线逼近的方法，用Autolisp语言编程实现复杂空间曲线的自动绘制，并利用DXF文件将图形信息传榆到MasterCAM软件中，生成CNC系统可以识别的NC代码。该方法为CNC系统中任意空间曲线的加工提供了一种有效方法。     

光电内窥参数检测装置

报导一种新的光电内窥参数测量装置。将一半导体激光器发出的光束经柱面镜汇聚成一细线,通过特殊设计的折反棱镜将其沿轴线方向投影到管孔内壁,得到管孔内壁的光截轮廓,该轮廓经物镜成像到CCD光敏面,通过图像卡采集到计算机。在计算机图像测量及辅助提示下,完成参数测量。此外,该装置还可在测量显微镜横向移动导轨及读数手轮的配合下测量内孔中径。实验结果表明轴向测量的重复精度为±17μm;中径测量的重复精度为±12μm.它在工业制造领域内具有广阔的应用前景。     

阀门变速驱动装置设计

介绍了可由上位微机进行远距离控制的阀门驱动装置，该装置可作为压力、流量等阀控参数在设定时间内作线性增量的控制设备，装置中包含了阀门特性测量功能。     

A method for the fabrication of thin-foil apertures for electron microscopy

A method is described for making thin foil apertures by piercing a plastic film with a heated microneedle and subsequently metallizing the plastic film by vacuum evaporation. Apertures can be made with diameters from 5 μm to 100 μm. They are round and very sharp-edged and can be made in various patterns and combinations of sizes.     

用Zernike多项式进行波面拟合的几种算法

介绍了几种实现波面Zernike 多项式拟合的常用算法。为避免因直接构造法方程组而引入计算误差,这些方法归结为两种思路：一是从基底函数系入手,通过变换函数族的基底来改善法方程组状态;二是直接从矛盾方程组入手,应用Householder变换把系数矩阵正交三角化,直接求解拟合系数。特别是第二种方法由本文第一次提出,它避免了构造法方程组,从而避免了以前的方法因构造的法方程组出现严重病态而引入的计算误差,并且易于编程,因而是一种比较理想的实现Zernike 多项式拟合的算法。     

General tool correction for five-axis milling

In this paper a method is presented by which cutter location data can be determined for any type of milling tools defined according to DIN 66215 whereby any point of the tool can be defined as the contact point. In addition, the cutter location point for 5-axis milling can be determined using a single formula for any type of milling tool.     

适于内燃机燃烧过程研究的高速摄影机信号同步系统

阐述了一种适于研究内燃机燃烧过程的高速摄影机信号同步系统。该系统通过发光二极管在高速摄影底片上打印信号编码 ,确定每幅燃烧图象对应的曲轴转角 ,实现图象与缸内燃烧爆发压力的严格对应。     

小型发电机交交变频模块的设计

为了缩小小型发电机变频装置的体积,降低变频装置硬件成本,本文设计了一种不同于传统交直交变频模式的交交变频的模块。应用单片机控制双向晶闸管的导通角,实现输出电压和频率的稳定。通过调节汽油机节气门的开度,实现输出功率的稳定。系统选用ATmega16微处理器,在精度的要求范围内能对电压进行快速稳定地调节。     

基于结构特征的路面裂纹病害检测算法

提出一种新颖的图像分解算法,用于复杂背景下的路面病害图像,可以获得较为清晰的裂纹病害信息。通过对含有局部线性特征的裂纹图像进行形态分析,建立与结构特征相匹配的基底,利用局部Ridgelet函数作为稀疏表示的基底,图像中的结构信息作为一种组成成分被提取出来,同时运用全变差正则化方法对提取的结构信息加以正则化约束,使得提取结果更加精细化。实验结果表明利用该算法提取的裂纹病害信息符合人眼的观测结果。     

基于脊曲线控制的参数曲面周期变形

为得到理想的参数曲面造型效果,构造了一种新的基于多项式的伸缩因子,它不仅具有已有伸缩因子的特性,还具有区域峰值性;同时引入脊曲线的概念,对曲面进行控制变形,从而对曲面进行雕刻;然后利用脊曲线实现对曲面的周期控制变形。实验结果表明,该方法计算简单、易于控制,可以得到丰富的变形效果,适用于几何造型、计算机动画、CAD/CAM等领域。     

风机性能计算机辅助测试系统

系统实现了风机性能参数的自动测试和计算,并可以对风机运行过程进行实时报警和远程通信。建立了风机性能测试数据库系统,以有效管理所有试验数据。     

利用R参数和条件转移指令实现球面数控铣削编程

球面类三维曲面铣削加工,许多人认为只有使用CAM软件进行自动编程方可实现,实际上只要充分利用SIEMENS(西门子)802D数控系统的R参数和条件转移指令,可以方便地实现球面的铣削手工编程。根据同样原理,还可以实现椭圆、倒圆、倒角等铣削加工,充分发挥系统的潜能。     

Flow imaging for multi-component flow measurement

For pseudo-homogeneous flows, measurements of density and mean velocity can give the component mass flow rate of a two-component mixture. However, for accurate measurement of non-homogeneous flow rate, the density and velocity distribution across the cross-section of the pipe must be known. The most practical way of obtaining this information is by using the flow imaging technique.

A recently developed capacitance system gives 60 frames per second images of oil/water flow in a 78 mm pipe. The target spatial resolution is one part in 20 by distance (one in 400 by area). The electrical properties of each imaged boundary are functionally related to the imaged value, so the component ratio of a two-component mixture within a boundary can be measured, although individual particles cannot be imaged. Design data shows how the basic system can be part of a complete system for component mass flow measurement.     

Stereological equations for phases within particles

Using data from sections, stereological equations can be used to estimate the volume-weighted averages of both the volume and the volume-squared of a set of particles. In mineral processing, the volume distribution of particles can be readily estimated using sieving, so it is uncommon to use stereological methods to determine the volume distribution of particles. A far more important application of stereology for mineral processing is to determine the volumetric grade distribution of minerals within particles. Different minerals or compounds within the particles are called phases. In this paper, stereological equations for estimating various volume-weighted averages are modified so that they can be applied to phases within particles. From these equations, various volume-weighted moments of the mineral grade distribution can be estimated. The equations are also modified so that the volume-weighted covariance of different phases can also be estimated. The equations derived are studied numerically by simulating sections though a double-capped sphere.     

一种用于多自由度非线性间隙值识别的改进恢复力曲线方法

在机械系统中,间隙无处不在,由间隙引起的接触非线性往往会严重影响系统的动态响应精度,从而降低系统的动力性能。如果能利用系统动态信息识别出间隙大小,就能为机械系统的间隙控制提供依据。针对多自由度含间隙非线性系统,提出一种结合传统恢复力曲线方法与矩阵行空间正交投影技术的间隙值辨识方法。通过激励力和响应加速度得到传统意义下的恢复力,将该恢复力投影到各非线性位置上,绘制投影恢复力关于对应位置位移的曲线,由曲线的拐点就可以准确地识别间隙值。经过仿真验证了该改进方法的可行性,并与其他方法进行对比显示了该方法的优越性。在设计的含间隙悬臂梁试验台上进行参数辨识试验,验证了该方法在真实试验条件下的有效性。     

高精度一维标定装置控制系统设计

为解决在科学测量中标定装置的精度、稳定性等问题,设计了基于At89s52单片机的高精度一维标定装置控制系统.该装置主要用于自动检测微距变化与位置标定.装置由单片机、步进电机、驱动器和滚珠丝杠组成,通过单片机来驱动步进电机,带动滚珠丝杠的运动而使平台移动.通过系统设置可以控制分辨率的大小.介绍了如何通过单片机实现控制的过程,以及对在控制系统设计的同时遇到的问题进行了解决.通过量块对于该装置的检定,精度达到10微米级.相比于一些大型高精度测量仪器,具有成本低,人机界面良好等优点.之后将进一步通过计算机通信技术来对数据的输入,实现更高的智能化.在沉降监测领域中,该装置可以用来模拟沉降量,进而对实验进行评估.     

Consteel振动输送机的水平运动建模

对于Consteel振动输送机,四轴惯性激振器产生水平激振力,槽体在拉杆作用下可看做一个倒立摆。当激振力为水平激振力且拉杆较长时,槽体在垂直方向的运动很小,可以看做只有水平运动。当不考虑物料与槽体的滑动,把物料看做附加质量时,得到槽体和基座的两自由度模型。当把基座看做固定不动时,得到槽体和物料的两自由度模型。同时考虑基座、槽体和物料得到一个三自由度模型,以便综合分析输送机的水平运动。     

A Generalized Interface for 16-Bit Computers

ABSTRACT

Most peripherals used by chemists for on-line experiments can be interfaced quickly and relatively inexpensively by taking a modular approach to the interface. The usual interface has been divided into three parts: a bus which distributes standardized signals for control and data, a module for the computer, and a module for each peripheral attached to the bus. Furthermore, the number of peripherals that can be attached to a computer can be easily expanded. Transistor-transistor logic and TTL-compatible circuitry have been used throughout.