机构综合的实根隔离算法研究

机构综合的大多问题都可以转化为非线性方程组全部解的问题。而现有的数值方法由于各自的弱点,使得人们对带有误差的数值方法不能放心,符号计算是精确计算,其特点是数值方法不具有的。研究了基于符号计算的实根隔离算法,给出了算法的步骤,运用了Maple9.0软件开发了计算程序,并对刚体导引四杆机构综合问题进行了计算,求得了全部解。     

机构综合的多实根隔离算法研究

机构综合的大多问题都可以转化为非线性方程组全部解的问题.而现有的数值方法由于各自的弱点,使得人们对带有误差的数值方法不能放心,符号计算是精确计算,其特点是数值方法不具有的.研究了基于符号计算的多实根隔离算法,运用Maple10.0软件开发了计算程序,该方法有效地应用近似因式分解,编程简单、分析直观、结果可靠.对四杆机构综合问题进行了计算,求得了全部解.     

小流量电液伺服阀叠合量气动测量台的研制

为了提高小流量电液伺服阀叠合量的测量效率,实现叠合量气动测量过程的自动化,分析了电液伺服阀叠合量气动测量方法的原理及特点,采用压力式和流量式气动测量方法实现阀芯自动对中和叠合量自动精确测量。从机械结构设计和控制系统方案上提出了自动化策略,研制了一套小流量电液伺服阀叠合量气动测量台,实现叠合量高精度测量的全过程自动化。通过实验和工程实践验证,该测量台的叠合量测量精度达到±0.5 μm,且重复精度达到±0.5 μm。     

彩色液晶显示模块在智能仪表中的应用

为了实现测量参数监控,开发了基于高性能微控制器和彩色显示模块的智能仪表,研究了监控参数的数值显示、曲线显示和柱状图显示方法。参数显示以中文提示与数值显示的方式,为了达到实时显示的目的,参数显示采用显示窗口尺寸固定与动态刷新窗口结合的方法。通过建立测量参数与显示模块像素之间的坐标转换关系,在显示模块上实现了测量参数的实时曲线和柱状图显示功能。并通过工程应用实例验证了方法的可行性。     

Estimation of section thickness,etc. by quantitative electron microscopy

Methods have been developed for the estimation of section thickness, and of the mass-thicknesses, and hence the masses, of material embedded in sections. They are based on the current densities measured with a Faraday-cage or on a new approximation for the relationship between exposure and optical density (OD) of the electron microscopical plate, which is valid for OD < 5. This relationship is quite distinct from the response to light, and also from an approximation for electrons which was only valid for OD < 1.2, and which was the basis for an earlier method. The old methods and the two groups of new ones were tested, and also compared with the interference microscope. It was found that all but one of the new methods, in both groups, were homogeneous; the older methods and the interference microscope differed very significantly between themselves and with the homogeneous methods. The errors in the interference microscopical estimations were almost certainly due to the presence of embedded material in the sections, which could not be detected with the interference microscope because of its low resolution and the poor contrast in the thin sections. (A second set of experiments using only pure resin gave a good agreement between the homogeneous methods and the interference microscope.) The orders of accuracy of the methods are quite high. A measurement repeated twelve to thirty-five times will yield a value which has a 95% chance of being within 5% of the true value, while a single observation has a 95% chance of being within ～ 25% of the true value with most methods, while some place it within ～ 10%. Simplified, but less accurate, applications of the methods are also suggested.     

从外部设定PLC定时器的几种方法

以OMRON CPM1A为例．介绍了用模拟输入电位器、拨码开关和按钮等方法改变定时器的设定值。     

Variational solutions for the nonlinear deflexion of an annular membrane under axial load

Variational methods are used to obtain a compatible and an equilibrium solution for the nonlinear deflexion of an initially unstressed annular membrane with a concentrated load applied along its axis of revolution. Both solutions are exact for a value of Poisson's ratio equal to one third; otherwise the calculated deflexions are in close agreement over a range of values of Poisson's ratio typical of many elastic materials.     

基于耦合源误差分析的转子振动信号识别方法

转子振动信号实时监测是保障旋转机械健康运行的关键,转子圆度误差和电涡流位移传感器误差的耦合源误差在以往的研究和振动监测中很少考虑,使得转子振动信号有一定的失真,甚至会引起误判。以实际转子为例,提出了圆度误差测量表达式;测量和分析了两种常用电涡流位移传感器的误差,利用傅里叶拟合方法构建了圆度误差和电涡流位移传感器耦合源误差表达式,建立了耦合源误差与转子振动信号之间的映射关系。提出了点-点法、平均值法与最大值法3种转子振动信号识别方法,3种方法都能有效识别转子振动信号,其中点-点法最精确,识别误差占比约20%;平均值法计算简便,识别误差占比约10%;最大值法偏保守,但可有效避免误判,识别误差占比约32%。     

基于Pro/E的公差分析在天线结构设计中的应用

公差分析是结构设计中的重要部分,公差分析方法分为极值法和统计法两类.文中介绍了两类公差分析方法,利用Pro/E的公差分析对产品装配的公差进行分析,并对相关零件公差进行评估和优化.分析结果表明,Pro/E的公差分析功能为产品设计的改进指出了方向,相比传统的经验设计,效率更高,对提高产品质量和降低产品成本有着明显的应用价值.     

电场仪标定系统设计

介绍了一种电场标定系统的原理、设计方法及应用。整个装置由单片机系统进行高精度数据采集控制,控制高压源输出高电压连接平行板模拟均匀电场,最终将电场仪测得的电场值送入上位机软件通过与理论电场值的对比达到标定的目的。通过对多台电场仪的标定,均获得了与理论计算值相符合的结果,为电场测量的可信度与对比度提供了可靠的依据。     

链板挤孔强化处理方法的研究

用试验方法确定了挤孔对链板疲劳寿命的影响 ,从理论上分析了在最佳挤孔量下链板疲劳寿命提高的因素 ,用有限元法计算了 16 A链板的最佳挤孔量 ,并与试验结果进行了比较 ,结果表明用弹塑性有限变形理论和有限元方法计算链出的板最佳挤孔量具有工程实际上的可用性。从而给出了计算链板最佳挤孔量的有效计算方法     

阀门压力试验的质量控制

论述了试验人员、采用标准、试验设备和试验方法等是影响压力试验质量的主要因素,提出了相应的质量控制措施。     

用阈值法自动分割某内燃机铁谱磨粒图像

利用计算机图像处理技术实现铁谱图像诊断自动化是铁谱技术发展的目标。铁谱原始图像需要平滑、滤波、磨粒分割等预处理,才能有效地减少噪声污染并简化数据处理。探讨了铁谱图像的预处理技术,采用自动阈值分割法对某内燃机铁谱图像进行处理,验证了该方法的有效性。     

Evaluation of material degradation on the basis of ultrasonic tomography during the detection of scattered signals

Evaluation of the operational degradation of materials using nondestructive methods is an urgent problem of materials science. The nucleation and accumulation of dispersed flaws in structural materials occur from the very beginning of their exploitation and lead to changes in material properties, nucleation of macrocracks, and finally damage. Phenomenological approaches, using both direct and indirect methods are used to study and evaluate flaws [1]. Fractography is a direct method. The measurement of “flaws” (as relative deviations from a standard value) in various physicomechanical characteristics (density, modulus of elasticity, or microhardness) and electrical resistance are classified as indirect methods.     

基于智能Agent的个性化产品定制

以个性化摩托车定制为具体应用 ,研究了在网络上利用 Java实现基于 Agent的个性化产品定制及其系统开发 ,提出个性化产品定制模板、个性化产品定制与柔性开发的内容匹配和个性化产品兴趣值的计算方法。     

基于循环经济的废旧工程机械产品无损拆解工艺

以废旧的工程机械产品为研究对象,为获得具有最佳修复价值的再制造毛坯,分析了工程机械产品可拆解性的影响因素及拆解方式,并以装载机为例,提出适合装载机自身特点的拆解工艺流程和方法。     

冲击加速度测试法在强夯实时检测中的应用

强夯法具有施工简单、效果好、费用低等优点,在多种地基土和各类工程,尤其大面积地基处理的工程中应用强夯法的优势很显著.目前,强夯施工时一般依据强夯技术规程采用测量夯沉量的方法来实时检测夯实程度.首先介绍了几种不同实时测量夯沉量的方法以及利用强夯冲击时夯锤的加速度或土的受力变换来实时检测夯实程度的方法.然后,通过实验发现加速度的峰值和作用时间与夯沉量有着非常紧密的关系.峰值的变化规律基本和累积夯沉量保持一致,作用时间的变换和单次夯沉量的变化类似.最后,提出了利用MEMS加速度传感器和无线芯片作为加速度采集系统的新方法.     

转子压缩机滚动活塞角速度的计算方法比较

转子压缩机滚动活塞角速度的计算对于压缩机的动力学分析至关重要,其计算方法有多种.近年来提出的简化解析式法及平均值法具有计算简便的特点,但其准确性方面却鲜有研究.以滚动活塞角速度的精确计算方法——迭代法为对比标准,利用MATLAB软件编写程序研究了两种方法(简化解析式法及平均值法)在计算活塞角速度时的计算精度,并研究了压...     

Research on Key Issues of Consistency Analysis of Vehicle Steering Characteristics

Given the global lack of effective analysis methods for the impact of design parameter tolerance on performance deviation in the vehicle proof-of-concept stage,it is diffiicult to decompose performance tolerance to design param-eter tolerance.This study proposes a set of consistency analysis methods for vehicle steering performance.The process of consistency analysis and control of automotive performance in the conceptual design phase is proposed for the first time.A vehicle dynamics model is constructed,and the multi-objective optimization software Isight is used to optimize the steering performance of the car.Sensitivity analysis is used to optimize the design performance value.The tolerance interval of the performance is obtained by comparing the original car performance value with the optimized value.With the help of layer-by-layer decomposition theory and interval mathematics,automotive performance tolerance has been decomposed into design parameter tolerance.Through simulation and real vehicle experiments,the validity of the consistency analysis and control method presented in this paper are verified.The decomposition from parameter tolerance to performance tolerance can be achieved at the conceptual design stage.     

Development of the LED measurement system of chromaticity coordinates correction

In this paper, we propose a procedure to adjust the chromaticity coordinates by using a few samples of the color measurement coordinate to do the error correction and choose the correction method of minimum color error difference average to be the procedure of measuring instruments, and to construct an efficient and predictable calibration procedure. This research adopts some engineering statistics methods, such as median and average methods, and corrects the experiments to obtain the chromaticity coordinates. The four calibration methods that we designed lower the average value of the color errors as 0.034. Moreover, the minimum average value of errors in the X-axis could be revised to 6.3% while the minimum average value of errors in the Y-axis 8.8%. The accuracy of best calibrated chromaticity coordinates could achieve to the percentage 71.1%.