评定直线度误差的最小区域法

直线度误差是一种常见的形状误差。它分为给定平面内、给定方向上和任意方向上的直线度误差三种。 直线度误差常用水平仪或自准直仪进行检测。将水平仪或自准直仪的平面反射镜放在根据被测长度选     

齿轮压力角或螺旋角误差的最小二乘法和最小区域法评定

本文通过分析最小二乘法评定齿轮压力角或螺旋角误差后,提出采用最小区域法进行评定,分析和比较结果表明,新方法使用简便,计算精度高。     

齿轮压力角或螺旋角误差的最小二乘法和最小区域评定

本文通过分析最小二乘法评定齿轮压力角或螺旋角误差后，提出采用最小区域法进行评定，分析和比较结果表明，新方法使用简便，计算精度高。     

直线度误差评定方法简述

本文简要叙述了用两端点法、最小二乘法和最小区域法来评定平面内直线度误差的求解方法和步骤。     

直线度误差的评定方法及其数学证明

介绍了平面内实际直线度误差最小包容区域的评定方法，并以初等方法给出了数学证明，对正确评定直线度误差及避免工作中的失误，有一定的帮助作用。     

评定直线度误差的精确算法与程序实现

本文讨论了评定直线度误差的计算机精确算法，给出相应的程序框图，并介绍了程序的实现方法。通过在实验室和企业中的实际运用，证明了该方法的有效性和程序的可靠性。     

评定直线度误差数据处理方法的分析与比较

用基础的测量方法和数据处理方法对直线度误差进行评定。测量方法采用水平仪的节距法。数据处理方法采用两端点连线法、最小二乘法、最小区域法。每一种方法都分别用计算法和作图法评定直线度误差。采用不同的方法对同一组数据评定直线度误差,其结果不尽相同,并对其精度进行比较,从而得出应用这三种方法评定直线度误差的差别。     

评定直线度误差的精确算法与程序实现

本文讨论了评定直线度误差的计算机精确算法,给出相应的程序框图,并介绍了程序的实现方法。通过在实验室和企业中的实际运用,证明了该方法的有效性和程序的可靠性。     

基于最小包容区域的球度误差评定方法

针对球度误差评定方法存在原理误差或模型误差,提出了一种符合最小包容区域定义的球度误差评定方法,即将几何搜索逼近算法与基于最小包容区域法的球度误差评定的几何结构和定义结合起来的准确评定方法。对仿真数据和其他文献中的数据进行了评定。所提方法与其他方法的评定结果表明,所提方法可以准确地找到最小包容区域球的球心并给出球度误差的精确解。     

基于最小二乘法的旋转风速仪误差校正研究

旋转风速仪测量误差会导致风电场发电机组发电量损失、电能质量下降。通过测量实验对比三杯式风速仪和超声波风速仪,得出误差产生的主要因素是3.5 m/s以上三杯式风速仪的"过高效应"。该文提出一种风速测量校正方法,基于最小二乘法对三杯式风速仪的测风误差进行校正,能有效减小风电场测风系统测量误差。     

Matrix-presentation linear least square error method of inverse elastic-plastic large deformation finite element model for upsetting

The main purpose of this paper is to develop the matrix presentation linear least square error method of inverse elastic-plastic large deformation finite element model for upsetting to obtain the friction coefficients during the upsetting process. This inverse model assumed the linear material and based on the modified experimental loading increments using the linear modified experimental upsetting loading standard proposed in this paper. Then the friction coefficients of contact boundary between the workpiece and the die at specific finite element analysis stages can be derived. Finally, using the cubic spline fitting, the history of friction coefficient during the upsetting process can be obtained. It is demonstrated that the workpiece profile of upsetting experiment is quite identical to the workpiece profile of simulation using the result obtained in this paper as the history of friction coefficient of contact boundary, and furthermore the distribution of stress and strain of the workpiece during upsetting process can be understood.     

A new minimum zone method for evaluating straightness errors

A new minimum zone method for straightness error analysis is proposed in this article. Based on the criteria for the minimum zone solution and strict rules for data exchange, a simple and rapid algorithm, called the control line rotation scheme, is developed for the straightness analysis of planar lines. Extended works on the error analysis of spatial lines by the least parallelepiped enclosures are also described. Some examples are given in terms of the minimum zone and least-squares. Finally, this easy-to-use method is illustrated by an example that demonstrates that, for a planar line, the minimum zone solution can even be found without the use of a computer.     

基于最小二乘法的智能校验方法

介绍了一种检测仪器的智能校验方法;着重描述了基于最小二乘法的校验算法;该智能校验方法充分利用微处理器的数据处理能力,使校验操作变得简单方便,同时降低了仪器对于内部器件稳定性的要求。     

一种机器视觉加权最小二乘解法

为了进一步提高机器视觉的重建精度,本文首次从参数方程的角度来重新审视机器视觉系统以及在此方程上提出了加权的最小二乘方法。机器视觉系统中,重建精度将随相机布局的不同而不同,即随相机与特征点的距离以及旋转矩阵的不同而变化。原有解算方法,并不区分这些不同,利用最小二乘法求取拟合误差最小点。针对这一不足,本文首先改变了机器视觉系统的基础,利用参数方程来描述系统模型,在此基础上,推导了加权的最小二乘方法,给有大误差布局的相机较小的加权,从而进一步提高精度。这种算法的关键是对权重的估计。文章最后的仿真和实验验证了本文算法的有效性。     

Application of neural network interval regression method for minimum zone straightness and flatness

The goal of this paper is to develop an accurate, efficient, and robust algorithm for the minimum zone (MZ) straightness and flatness. In this paper, we use an interval bias adaptive linear neural network (NN) structure together with least mean squares (LMS) learning algorithm, and an appropriate cost function to carry out the interval regression analysis. From the results, we can see that both the straightness and flatness results from the interval regression method by NN can converge closer to the definition of the MZ straightness and flatness, respectively, than that of the least-squares (LSQ) method. The interval regression method by NN developed in this paper is applicable in the linear regression analysis that has a complicated constraint, and where the LSQ method cannot be used.     

Monte carlo method for the uncertainty evaluation of spatial straightness error based on new generation geometrical product specification

Straightness error is an important parameter in measuring high-precision shafts. New generation geometrical product specification(GPS) requires the measurement uncertainty characterizing the reliability of the results should be given together when the measurement result is given. Nowadays most researches on straightness focus on error calculation and only several research projects evaluate the measurement uncertainty based on "The Guide to the Expression of Uncertainty in Measurement(GUM)". In order to compute spatial straightness error(SSE) accurately and rapidly and overcome the limitations of GUM, a quasi particle swarm optimization(QPSO) is proposed to solve the minimum zone SSE and Monte Carlo Method(MCM) is developed to estimate the measurement uncertainty. The mathematical model of minimum zone SSE is formulated. In QPSO quasi-random sequences are applied to the generation of the initial position and velocity of particles and their velocities are modified by the constriction factor approach. The flow of measurement uncertainty evaluation based on MCM is proposed, where the heart is repeatedly sampling from the probability density function(PDF) for every input quantity and evaluating the model in each case. The minimum zone SSE of a shaft measured on a Coordinate Measuring Machine(CMM) is calculated by QPSO and the measurement uncertainty is evaluated by MCM on the basis of analyzing the uncertainty contributors. The results show that the uncertainty directly influences the product judgment result. Therefore it is scientific and reasonable to consider the influence of the uncertainty in judging whether the parts are accepted or rejected, especially for those located in the uncertainty zone. The proposed method is especially suitable when the PDF of the measurand cannot adequately be approximated by a Gaussian distribution or a scaled and shifted t-distribution and the measurement model is non-linear.     

基于递推最小二乘法的地磁测量误差校正方法

针对弹体地磁测量容易受到各种误差影响而导致地磁姿态测量精度降低的问题,在分析自身误差和环境误差的基础上,对椭球模型的地磁测量误差进行建模,采用最大似然估计解算静态误差补偿参数,以解算结果为初值,通过递推最小二乘法推到补偿参数的实时更新算法,综合以上研究,形成用于地磁测量误差补偿的在线组合校正方法。仿真及实验结果表明,在接近盲区方向的最大姿态角误差小于5°,在线组合校正能够保证姿态检测系统在不同射向条件下的精度。     

基于遗传算法的平面直线度误差的精确计算

提出一种基于遗传算法的平面直线度计算方法,该方法计算原理简单,借助于计算机技术,可以较容易地实现计算精度要求较高时的直线度误差计算。文章首先给出问题的计算模型。接着介绍了在遗传算法实现中的关键技术,包括染色体个体的表达、初始群体的产生方式、适应度函数、遗传算子(选择、交叉和变异等)的确定、遗传运算的停止准则等。最后应用实例对算法进行了验证计算和分析,结果表明,所设计的基于遗传算法的平面度误差计算方法可以实现平面直线度的精确计算。