电子称重仪的精度分析

分析了OCS -XY型称重仪的误差产生原因 ,并在其基础上 ,利用微处理器的软硬件技术对系统误差、偶然误差和疏失误差进行了校正 ,从而有效地提高了产品的测量精度 ,使得该称重仪具有了较高的可靠性和推广性。     

利用光纤光栅制作动态称重仪

为了克服目前使用的公路汽车动态称重仪的成本高、误差大、使用寿命短等缺陷,提出了利用光纤光栅制作动态称重仪的方案.通过把光纤光栅镶嵌在光纤加强复合材料中,利用光栅为传感元件测量横向负载,设计了一种汽车动态称重轴重仪,并进行了初步的实验.实验结果及分析表明我们设计的光纤光栅动态称重仪具有很高的灵敏度和较大的称重量程.     

一种基于ADμC816的高精度工业称重仪

介绍了应用新型ADμC816芯片为核心研制的工业称重仪的基本功能及其组成框图，并对该称重仪的应用技术特点作了较为详细的说明。     

高密度介质自动补给装置磁铁粉称重仪的设计

文章介绍了高密度介质自动补给装置磁铁粉称重仪的硬件结构及工作原理,详细阐述了称重仪压力传感器和速度传感器的选型,给出了流量在线测量的实现方法。该称重仪采用称重传感器测量胶带输送机上的物料重量,并以AT89C52单片机为计算和控制的核心元件,对传感器送来的信号进行分析、控制、处理和驱动显示,实现了重量的在线动态测量和控制。     

称重仪F701在切片包装系统中的应用

文章介绍了称重仪F701在切片包装系统中的应用。     

一种新型称重仪的系统构成及改进

介绍了一种用于大工业称重系统的新型电子称重仪,该称重仪采用了单片机技术,不仅使电路设计简单,便于调试和安装,而且由于软件编制的灵活性,还可以实现信号的自动采集,校正和处理。有效地提高了产品的测量精度,具有较高的可靠性和推广性。     

动态称重仪在研制中的分析和计算问题

本文阐述了在动态称重仪研制过程中用有限元法对结构进行强度，刚度校核，提出了应变测量区的参考尺寸，根据面板中心线上各点的应变影响线，找出应变片的分布规律和具体位置，使一定重量的车辆压在动态称重仪的任何位置上都可测出其准确重量。     

微机在汽车载体自动称重仪中的应用

介绍了汽车载体自动称重仪一次仪表的工作原理及二次仪表的测量放大电路、主电路、逆变电源电路设计与软件设计。     

炼焦过程微机监控系统

系统主要由称重仪、上位机和大屏幕显示仪三部分组成。称重仪TFOLEDO 8142接收传感器送来的毫伏信号,输出一路4mA～20mA电流信号到焦炉顶部的大屏幕显示仪供煤车司机监视,另一路输出以RS-232协议与上位计算机通信,将重量信号送到计算机处理。上位机中用VFP6.0开发了动态数据库管理系统对称重信号进行处理。上位机中内置了PCL-725开关量接口模板,输入两路煤车对位信号,输出4路打铃、打笛信号控制装煤车工作。     

便携式机车车辆动态称重仪的研制

基于现有轨道线路,研制一种仅需在两轨道之间放置称量装置,通过车轮轮缘将重量传递给称量装置进行测量的、便携的、高精度动态电子称重仪;设计了便携式轨道车辆应变式称重传感器,进行了传感器结构设计及弹性体强度分析;采用USB数据采集卡进行数据采集;基于labVIEW开发程序进行动态称重信号的处理,并实现可视化界面,得到重量值;此称重仪具有便于携带、安装方便、操作简单、成本低、可靠性高等特点,适用于各种铁路轨道车辆的现场动态称重.     

A Posteriori Estimates for a Natural Neumann–Neumann Domain Decomposition Algorithm on a Unilateral Contact Problem

In this paper we present an error estimator for unilateral contact problems solved by a Neumann–Neumann Domain Decomposition algorithm. This error estimator takes into account both the spatial error due to the finite element discretization and the algebraic error due to the domain decomposition algorithm. To differentiate specifically the contribution of these two error sources to the global error, two quantities are introduced: a discretization error indicator and an algebraic error indicator. The effectivity indices and the convergence of both the global error estimator and the error indicators are shown on several examples.     

硅微陀螺仪的误差分析

以z轴硅微陀螺仪为研究对象,对加工误差产生的误差信号进行了分析.由于加工误差,使得陀螺仪结构不对称,主要表现为支承梁不对称、梳齿间距不等,产生了不等弹性、阻尼不对称以及力不平衡这三种现象.以动力学方程为基础,分析了不等弹性和阻尼不对称产生的误差信号;以静电理论为基础,分析了驱动梳齿和敏感梳齿间距不等时产生的误差信号.分析结果表明,这些误差信号包含了正交耦合误差和与有用信号同相位的误差信号.最后,介绍了一种减小正交误差的方法,并进行了仿真.     

Robot calibration using the CPC error model

The complete and parametrically continuous (CPC) robot kinematic modeling convention has no model singularities and allows the modeling of the robot base and tool in the same manner by which the internal links are modeled. These two properties can be utilized to construct robot kinematic error models employing the minimum number of kinematic error parameters. These error parameters are independent and span the entire geometric error space. The BASE and TOOL error models are derived as special cases of the regular CPC error model. The CPC error model is useful for both kinematic identification and kinematic compensation. This paper focuses on the derivation of the CPC error models and their use in the experimental implementation of robot calibration.     

Adjoint-based error estimation and grid adaptation for functional outputs: Application to two-dimensional, inviscid, incompressible flows

Adjoint-based error estimation and grid adaptive procedures are investigated for their robustness and effectiveness in improving the accuracy of functional outputs such as lift and drag. The adjoint error estimates relate the global error in the output function to the local residual errors in the flow solution via adjoint variables as weight functions. These error estimates are used as a correction to produce improved functional estimates. Based on this error correction procedure, two output-based grid adaptive approaches are implemented and compared. While both approaches strive to improve the accuracy of the computed output, the means by which the adaptation parameters are formed differ. The first approach strives to improve the computable error estimates by forming adaptation parameters based on the level of error in the computable error estimates. The second approach uses the computable error estimates as adaptation parameters. Grid adaptation is performed with h-refinement and results are presented for two-dimensional, inviscid, incompressible flows.     

Local and global error estimations in linear structural dynamics

The study discusses the concept of error estimation in linear elastodynamics. Two different types of error estimators are presented. First ‘classical’ methods based on post-processing techniques are discussed starting from a semidiscrete formulation. The temporal error due to the finite difference discretization is measured independently of the spatial error of the finite element discretization. The temporal error estimators are applied within one time step and the spatial error estimators at a time point. The error is measured in the global energy norm. The temporal evolution of the error cannot be reflected. Furthermore the estimators can only evaluate the mean error of the whole spatial domain. As the second scheme local error estimators are presented. These estimators are designed to evaluate the error of local variables in a certain region by applying duality techniques. Local estimators are known from linear elastostatics and have later on been extended to nonlinear problems. The corresponding dual problem represents the influence of the local variable on the initial problem and may be related to the reciprocal theorem of Betti–Maxwell. In the present study this concept is transferred to linear structural dynamics. Because the dual problem is established over the total space–time domain, the spatial and temporal error of all time steps can be accumulated within one procedure. In this study the space–time finite element method is introduced as a single field formulation.     

基于边缘检测的动态误差分散半色调算法

针对数字半色调技术中的传统误差分散方法因误差分散系数固定而导致图像真实细节损失的问题,提出了一种基于边缘检测的动态误差分散算法。该方法沿着每个像素的误差分散方向进行边缘检测,再根据边缘检测结果动态地选择该像素各个方向的误差分散系数,减小了误差分散过程中的误差积累。实验表明,此方法可以明显改善由于误差分散系数固定而引起的图像轮廓细节损失。     

交替测量式掘进机定位系统误差建模与分析

交替测量式掘进机定位技术在多次交替测量过程中会产生累计测量误差,从而影响掘进机定位精度。目前主要围绕单次测量误差产生原因、误差分布规律及误差减小方法展开研究,未有针对多次交替测量误差分布规律的研究成果。通过分析交替测量式掘进机定位系统工作原理及定位过程,构建了掘进机定位误差模型。采用作图法验证误差模型的正确性,结果表明作图法与误差模型得到的定位误差基本一致,二者仅存在10^-3数量级误差。通过误差模型研究了角度测量误差、测距误差、推移步长及掘进机与测量平台间距对掘进机定位误差的影响,结果表明:角度测量误差越大,定位误差曲线的曲率越大,即误差增大越快,且Y_T轴定位误差增大速度远大于X_T轴;测距误差对X_T轴定位误差影响较大,测距误差越小,初始X_T轴定位误差越小,但误差变化速度不受影响;随着推移步长增大,Y_T轴定位误差曲线曲率增大,即Y_T轴定位误差增大速度加快;掘进机与测量平台间距和推移步长对掘进机定位误差的影响基本是等效的。采用正交试验方法分析了各因素对掘进机定位误差的影响程度,结果表明:测距误差对X_T轴定位误差影响最大,其次为角度测量误差,推移步长和掘进机与测量平台间距影响最小且二者影响程度一致;角度测量误差对Y_T轴定位误差影响最大,其次为推移步长和掘进机与测量平台间距且二者影响程度一致,测距误差影响最小。通过极差分析方法得到了降低定位误差的最优参数组合。     

基于软件故障注入的星载系统错误传播研究

设计了信号故障传播率的计算方法,在此基础上设计了根据信号故障传播率进行故障注入实验,并根据故障注入实验的结果绘制错误传播图的方法.根据实验结果和错误传播图可以从信号和模块两个层次对系统进行分析,找出最为脆弱的部分,即找出最可能传播故障的信号和模块,以及最可能传播故障的一条路径.据此可对系统的可靠性做出评测.工作在高辐射环境下的各类软件系统,如星载系统,在运行过程中可能会因环境的扰动发生SEU现象,本文利用软件故障注入技术对这种现象进行模拟,进行故障注入实验,实验结果表明我们设计的算法能有效地对系统的可靠性做出评测.     

虚拟测试系统的测试误差分析

在测试系统中,测试误差影响测试数据的精度.消弱其对测试结果的影响是至关重要的.首先讨论了随机误差的分布、测度,然后建立两种数据模型:基于LabVIEW平台的参数测试系统观测数据模型和理想数据模型.以此模型为基础,分析数据中的系统误差和研究系统误差的检验方法.提出了基于后验检验统计的系统误差检测法.最后修改观测数据的模型.结合此模型研究系统误差和随机误差的评定指标.     

A Posteriori Error Estimators for a Class of Variational Inequalities

In this paper, we present an a posteriori error analysis for the finite element approximation of a variational inequality. We derive a posteriori error estimators of residual type, which are shown to provide upper bounds on the discretization error for a class of variational inequalities provided the solutions are sufficiently regular. Furthermore we derive sharp a posteriori error estimators with both lower and upper error bounds for a subclass of the obstacle problem which are frequently met in many physical models. For sufficiently regular solutions, these estimates are shown to be equivalent to the discretization error in an energy type norm. Our numerical tests show that these sharp error estimators are both reliable and efficient in guiding mesh adaptivity for computing the free boundaries.