Error separation in CMM coordinate metrology

Form error measurement is a critical exercise in providing measures for the quality control in the precision manufacturing industry.Coordinate measuring machine （CMM） is one of the automated systems used in the accurate and precise dimensional measurements and geometrical form.This paper aims to study the effect of dynamic original unforeseeable errors at different undulations per revolution （UPR） of standard artifact measurement using selected two types of CMM touchtriggering stylus.Stylus-type and stylus-speed parameters were adopted and utilized throughout the course of experiment.The results are analyzed using fast Fourier transformation to obtain foreseeable geometrical errors due to CMM machine structure and stylus scanning speeds.The results of experiment successfully indicate that the number of UPR plays an important role in determining the CMM accuracy level of the roundness measurement result.Some specific error equations for stylus system and machine structure responses have been postulated and analysed to empirically predict the accuracy of PRISMOBridge-CMM-type at National Institute for Standards （NIS） in egypt.

Application of Large-Scale Systems Theory in Fire Control Systems

According the to the model of single tank fire control system, this paper makes use of decomposition-coordination theory of large-scale systems to discuss the shooting problem of multiple tank the control systems, and alalyzes specifically the three-tank the control systems and models.the process was imitated in computer, and the optimal shooting element of 3TS system was got. In addition, probability of hitting the target was calculated.

Sewage flow optimization algorithm for large-scale urban sewer networks based on network community division

By considering the flow control of urban sewer networks to minimize the electricity consumption of pumping stations, a decomposition-coordination strategy for energy savings based on network community division is developed in this paper. A mathematical model characterizing the steady-state flow of urban sewer networks is first constructed, consisting of a set of algebraic equations with the structure transportation capacities captured as constraints. Since the sewer networks have no apparent natural hierarchical structure in general, it is very difficult to identify the clustered groups. A fast network division approach through calculating the betweenness of each edge is successfully applied to identify the groups and a sewer network with arbitrary configuration could be then decomposed into subnetworks. By integrating the coupling constraints of the subnetworks, the original problem is separated into N optimization subproblems in accordance with the network decomposition. Each subproblem is solved locally and the solutions to the subproblems are coordinated to form an appropriate global solution. Finally, an application to a specified large-scale sewer network is also investigated to demonstrate the validity of the proposed algorithm.

Light pen whole space coordinate measuring system based on a tracking turntable

Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.

Williams-Otto Plant Control Based on Production Planning Associated to Coordinated Decentralized Optimization and Plantwide Control Techniques

Manufacturing plants are increasingly complex and integrated, requiring control systems able to identify the interactions between the various operating units. Production planning and control design of a process are tools that, if combined, bring many economic benefits to the processes since they aim to identify and maintain optimal decision operations to a system. This work uses such integration between production planning and plantwide control to propose a control system for the Williams-Otto plant from the definition of the operating optimal point for coordinated decentralized optimization, in which the original optimization problem decomposition into smaller coordinated problems ensure that the found local optimum also meets the requirements of the global system. The results for decentralized optimization are satisfactory and very similar to the global optimum problem and to the control system response proposed based on the optimal obtained. It is effective taking smooth actions, working with （economic） optimal set points （economically） of operation. The unification of production planning techniques and plantwide control techniques is an effective tool for the control system design for entire plants.

Dynamic Coordinated Management Model of Programme in Large-Scale Construction Company

Large-scale construction companies develop rapidly when facing more and more opportunities and challenges of programme contracting. However, project management technology, not meeting the requirements of firm growth, still stands proud, while relevant programme management methods have not been well studied. Therefore, this paper commences innovative application of coordinated management theory to programme management according to the need of changing the existing management mode in large-scale construction companies,then puts forward the dynamic coordinated management model composed of the dynamic coordination of function module, interface module, support module and evaluation module. Besides, coordination degree was introduced to make auxiliary analysis, so that companies can utilize internal and external resources more effectively to realize the goals of programme management as well as enterprise strategy.

用脉冲星的脉冲序号复现坐标时方法

为实现包括地球和地球以外的时间统一,需要运用相对时间观的两种时间来替代目前时间计量体系中的标准时间,这两种时间分别是:原时和坐标时,其中坐标时可溯源到脉冲星时间基准上。为构建简单的本地轨道参数历表,阐明分层嵌套的空间包含关系,形成时间相对统一的观点。从计量角度,提出了一种脉冲星复现坐标时的理论,运用相对时间观中的时间和空间不可分割观点,归纳了统一时间的广域坐标系所必须具备的基本特征,强调了原点观者的特殊性,提出了基于原点观者的脉冲星脉冲序号和初始历元的定义方法。首先,把一组脉冲星的脉冲序号约定为坐标时基准,用来复现坐标时,约定一组脉冲星的脉冲周期为固定的常数数组,约定后不再测定,常数的单位仍是国际单位制[秒],常数可理解为脉冲序号的坐标时间隔与[秒]之间换算的系数。然后,基于平面电磁波模型,把脉冲星的脉冲电磁波经过原点的时刻与脉冲序号一一对应,于是原点观者的坐标时与连续的脉冲序号成为线性函数关系,最后,分析了脉冲星稳定特点,给出了以一组序号为变量的脉冲星集合稳定性判据。

一种小型激光跟踪测量系统的研制

为实现大尺寸范围内的坐标跟踪测量,研制了一种小型激光跟踪测量系统。设计了光机电一体化的机械结构,实现减小系统体积与提高抗干扰能力。设计了系统的光学模块,通过优化基于位置敏感探测器的目标偏差量采集部分的光路,实现目标允许最大偏差量的增大。通过开展位置敏感探测器的标定实验,完成位置敏感探测器的线性区间与偏差比例系数的测量,为跟踪控制算法开发提供了关键参数。进行了跟踪控制模块的设计,并完成跟踪控制算法的开发,实现系统的快速跟踪测量。开发了系统三维可视化测量软件,实现用户对系统与目标的空间位置及运动状态的实时掌控。实验结果表明,系统的跟踪稳定性与位移分辨力分别为20μm和40μm,系统的跟踪速度最高可达480 mm/s,加速度最高可达506 mm/s^(2),跟踪距离范围不小于70 m,具有三维坐标测量与三维可视化功能,与现有跟踪仪相比具有体积、重量以及测角范围上的优势,具有良好的跟踪性能与应用前景。

手持GPS导航及定位精度分析研究

为解决手持GPS量值溯源难题,本文从基线场观测墩固定间距直接比较法、观测墩坐标点法及室内便携式导航信号源法,对手持GPS导航及定位精度进行研究分析。实验证明:基线场观测墩固定间距比较法可将其控制在±5m以内;观测墩坐标点法受外界环境条件影响较大,造成测量精度(±10m以内)明显下降;室内便携式导航信号源法受外界环境条件影响较小,测量精度较高,且控制在±3m以内,满足精度等级±5m检测需求。

数字经济助力中国式现代化:理论逻辑与经验证据

文章分别构建了中国式现代化与数字经济评价指标体系,使用熵权TOPSIS法对指标赋权,基于我国30个省份的面板数据测算了2013—2021年中国式现代化与数字经济发展水平,并对数字经济助力中国式现代化的作用机制进行了理论分析与实证检验。结果表明:(1)我国数字经济与中国式现代化的发展已取得一定成效,但区域发展不均衡。(2)数字经济的发展推动了中国式现代化发展,创新能力、城乡协调发展在其中发挥着重要的中介作用。(3)数字经济对中国式现代化的影响具有显著的空间溢出效应。

Coordination of PSS and FACTS Damping Controllers to Improve Small Signal Stability of Large-scale Power Systems

This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.

坐标测量技术半世纪——演变与趋势

坐标测量技术是现代制造和测量水平的重要标志.回顾了坐标测量技术发展的十大标志性事件,从测量范围及精度、探测技术、控制系统、测量软件、精度评定与溯源技术等角度概述了坐标测量技术的现状.预测应用于生产现场的开放性、兼容性和柔性俱佳的坐标测量控制技术,多传感器信息融合技术,智能坐标测量技术以及远程校准技术等将成为坐标测量技术的发展趋势.

基于标准器的大尺寸测量系统坐标统一化方法

针对大尺寸测量系统坐标统一化过程中公共点的测量误差不可控制的问题,提出了利用可现场溯源的标准器取代传统的独立公共点的方法。设计了一种标准器,并用更高精度等级的三坐标测量机对标准器上各个目标点之间的空间几何位置关系进行标定,把这些几何位置关系作为约束条件。现场应用中多站大尺寸测量仪分别测量标准器上的目标点,计算出各个几何关系与通过标定的约束关系之差,将这个差值与设定的误差限进行比较,确定公共点的测量值是否有效。对该方法进行了理论分析和仿真证明。提出了7参数坐标配准算法对大尺寸测量进行空间坐标数据配准。用激光跟踪仪和激光雷达及4个标准器进行现场实验,实验结果与传统方法相比,坐标配准误差得到降低。为了进一步验证该方法的有效性,把一根经过检定的基准尺放置于测量空间的12个不同位置,使用标准器约束前后的两组坐标配准参数分别计算基准尺长度的平均值和标准差。实验结果表明,使用标准器约束方法能够提高大尺寸测量系统坐标统一化精度。

经济型大尺寸激光自动坐标测量系统

利用手持式激光测距仪和二轴转台,设计了一种经济型大尺寸激光三维自动测量系统,用于船舶等大型工件的现场测量。介绍了系统的测量原理和主要组成部分,系统无需合作目标,在计算机的控制下自动对目标进行测量来获得相对系统的三维坐标数据。分析了系统的主要误差对测量结果的影响,完成了主要误差的提取实验。最后,利用激光跟踪仪对系统测试水平两点间的距离的测量精度进行了评定,并对船分段模型进行了测量实验。实验表明,该系统对水平放置物体的两点间距离的测量精度达到了1.73mm,对船分段模型的平行平面之间的距离测量精度达到了1.5mm。由于系统构成简单,硬件成本较低,测量精度较高,测量速度大约为1point/s,非常适用于船分段的测量。

仿生计量学的新领域──视觉坐标测量机

介绍了当代仿生计量学的新领域视觉坐标测量机，并描述了各类视觉坐标测量机的特点、测量原理、应用领域、可以达到的测量准确度和发展前景。

二维曲线自动跟踪测量的一种新算法

商品坐标测量机软件的二维曲线自动跟踪测量功能在应用中经常出现跟踪失败和采样信息不充分等问题。针对这些问题 ,提出了一种基于三次样条曲线基本性质的二维曲线自动跟踪测量算法 ,采用圆弧外插方法估算后续测量点并利用回溯方法提高跟踪测量的可靠性。这种方法还可以推广应用于曲面的扫描测量和一些特殊的三维曲线的自动跟踪测量中。文中还对测头补偿问题进行了分析 ,提出了相应的解决方法。

基于多边法的三维坐标测量系统自标定最优方案

研究了基于多边法的三维坐标测量系统的自标定问题 ,并首次给出了四路激光跟踪干涉仪和测量点布局的一些指导性原则。首先从系统自标定的数学模型入手 ,指出影响系统自标定的各个因素。通过大量的计算机仿真 ,研究各个因素对系统自标定的影响规律。最后综合得到了系统自标定应遵循的一些指导性原则 ,这些原则对于实际操作时进行合理的系统自标定。

多路激光跟踪干涉三维坐标测量系统冗余技术

介绍了冗余技术在多路激光跟踪干涉三维坐标测量系统中的应用。在分析激光跟踪干涉仪工作原理的基础上 ,采用 3 n[G]表决冗余方式 ,进行了系统的冗余设计。详细论述了基于系统的冗余技术实现的各种重大作用如系统的自标定、挡光自恢复和误差补偿等。

坐标测量机对凸轮曲线的测量与拟合及其评价

坐标测量机测量凸轮时,确定工件坐标系是一大难题。文中提出一种方法,可以从凸轮任意位置开始检测,仅测量一次凸轮轮廓,所有的测量数据均用于建立被测凸轮的工件坐标系,并可使测量误差、形位误差对凸轮工件坐标系建立的影响降低至最小程度。此外还提出了一种修正开关式球测头半径的计量学方法。