脉冲大电流校准及溯源技术研究

为解决1~100kA的脉冲大电流校准问题,建立了脉冲大电流校准系统,开展了脉冲大电流校准及溯源技术研究。校准系统由脉冲大电流发生装置、脉冲分流器组、光纤电流传感器、罗氏线圈电流传感器、宽带数据采集系统及测量软件组成;通过该校准系统,可开展脉冲幅度为1~100kA,持续时间为20μs~100ms的脉冲大电流发生/测量系统的校准,开展罗氏线圈传感器、光纤电流传感器等测量器具的校准,校准不确定度优于1%。     

旋转状态下微波叶尖间隙传感器校准影响因素分析

主要针对应用于发动机叶尖间隙测量的微波叶尖间隙传感器的校准需求,对测量原理、传感器的校准原理等进行了详细阐述,并分析了转速和回缩值等对校准结果的影响。为微波叶尖间隙传感器的进一步优化设计及应用提供了数据依据。     

变压器工频短路电流测量技术研究

针对变压器工频短路电流测量需求,研究了外积分式罗氏线圈技术和光纤电流传感技术。建立了2种传感器的低频数学模型,基于MATLAB/Simulink仿真计算传感器对工频短路电流的响应特性,结果表明:罗氏线圈对工频短路电流的测量精度受其下截止频率影响,下截止频率越低,测量精度越高;光纤电流传感器理论上可以精确复现工频短路电流。采用多种电流传感器进行变压器工频短路电流现场对比测试,结果表明:电流比较仪、光纤电流传感器及下截止频率为0.02Hz的罗氏线圈测得的电流波形吻合较好,而下截止频率为0.2Hz的罗氏线圈测量结果出现了明显的偏移,且无法归零,与仿真分析结论基本一致。对于外积分式罗氏线圈,为保证高精度测量,建议下截止频率应低于0.1Hz;光纤电流传感器具有极好的直流及低频响应特性,是工频短路电流高精度测量的理想方案。     

用于心磁传感器测试系统的三轴向亥姆赫兹线圈的设计与仿真

心磁检测对于心脏相关疾病的诊断具有独特优势，在用于测量心脏磁场的传感器(下称心磁传感器）的研制过程中，需要在模拟心磁的磁场环境下进行测试工作。基于此，设计了一个用于心磁传感器测试系统的亥姆赫兹线圈，它可以产生磁感应强度为pT级的动态磁场，模拟心磁环境，以满足心磁传感器测试的需求。根据亥姆赫兹线圈的磁场产生原理，使用磁屏蔽筒对环境磁场进行屏蔽，通过计算确定了线圈尺寸、线圈匝数、导线长度及导线横截面直径等参数。使用COMSOL Multiphysics仿真软件对亥姆赫兹线圈产生的静态磁场的分布均匀性以及通入线圈电流变化时磁场的动态特性进行仿真分析。仿真结果表明，所设计的亥姆赫兹线圈满足设计要求，能够产生磁场强度为100 pT左右、均匀度小于5%、波形实时性好的类心脏磁场波形，为心磁传感器的测试提供了良好的测试环境。所设计的亥姆赫兹线圈能够用于心磁传感器的测试工作，为心磁传感器的实际应用奠定了基础。     

曲面间隙测量电涡流传感器探头的性能研究

针对曲面间间隙测量的实际应用,从电涡流传感器的检测原理出发,对传感器探头的测量性能进行了研究．在平面线圈磁场分布计算的基础上,通过修正得到了曲面线圈的磁场分布规律,进而对线圈的测试性能进行分析和预测,实现了线圈参数的优化设计．同时,对曲面测量的各种影响因素进行了分析和试验验证,为电涡流传感器应用于曲面测量提供参考和依据．     

Rogowski Sensor for Plasma Current Measurement in J-TEXT

Rogowski coil is very useful in transient current measurement. Rogowski sensor consisting of Rogowski coil and integrator is one of the most important diagnostic instrumentations in Tokamak. In recent years, new structures of Rogowski coil based on printed circuit board (PCB) are developed to replace traditional handmade Rogowski coil for more excellent accuracy, better temperature stability, more accordant mutual-inductance, more symmetrical windings, and other advantages. However, the existing structures of Rogowski coil based on PCB are useless in Tokamak because the required Rogowski coil installed on the vacuum vessel should have long diameter and little space. This presentation provides a new twin-loops Rogowski coil (TRC) consisting of several PCB strips. TRC has all the advantages of existing PCB Rogowski coils and can meet the limited space requirement in Tokamak at the same time. A special experiment is carried out to prove that the mutual-inductance of TRC is immune to the variation of center position of plasma current. Moreover, a differential long-term integrator is designed to cooperate with the TRC. Two switches are used in the integrator to release the remaining electric charges on integrating capacitors once the measurement is over. Then, the error accumulation of integrator is canceled in repetitious measurements. The designed new Rogowski sensor can be used to measure long pulse current below 1 s.      

Static calibration of transducers using Gauss-function-basedapproximation

The problem of static calibration of measurement channels is considered under an assumption that the raw result of measurement depends both on a scalar measurand and on a scalar influence quantity. The methodology of calibration based on the Gauss-function approximation is developed and examined using synthetic data representing a measurement channel with a fiber-optic sensor. Various algorithms of calibration are compared; the accuracy of measurements, based on the results of calibration, is used as the main criterion of comparison. Some recommendations are formulated, concerning the applicability of the compared algorithms of calibration     

基于数字图像识别和光纤传感器的直流大电流在线校准装置

在电解冶金和电化学工业领域,大量霍尔直流超大电流传感器无预留校准接口.针对这一实际问题,设计了一种基于数字图像识别和光纤电流传感器的直流大电流在线校准装置.该在线校准装置以光纤电流传感器为标准,利用图像传感器实时采集霍尔电流传感器二次显示仪表的示数图像,对采集到的图像进行灰度化、中值滤波、二值化、闭运算、字符分割等预处...     

压阻式真空传感器校准技术研究

随着科学技术的发展,各种类型真空传感器在真空测量设备中得到广泛应用,日常测量和校准问题也日益得到相关计量部门的关注。通过对压阻式真空传感器使用原理的分析,采用比较法真空校准装置,获得真空变量与测量输出信号问的函数关系,对照测量误差是否在准确度等级范围内,准确判断测量结果与被测量真值的一致程度,解决该类型真空传感器的测量和校准问题。     

A new surface transducer for generating and detecting magnetic field transients in ferromagnetics

A new surface transducer is described for generating and detecting magnetic field transients or magnetization discontinuities in ferromagnetic materials [8]. The sensing is based on searching for transients of the magnetic potentials which would be likely to occur on the surface of the specimen. A coil core of high-frequency ferrite is used for this. The sensor theory presented shows the coaxial geometry of the coil core to be that which is more practicable for limiting detection to a compact volume of the specimen to be analyzed. The fundamental noise and disturbance analyses performed show adequate margins for wideband noise and external stray field disturbances. The transducer electronics for generating the varying external magnetic field in the specimen and for detecting the occurring field transients are described with a view to the optimization of the electrical circuits, and the resulting specifications are discussed. The surface transducer constructed is widely applicable for studying the magnetization characteristics of different ferromagnetics nondestructively in conjunction with stochastic-ergodic analyzers such as a pulse-height analyzer or a digital correlator through a punch-tape recorder or in on-line connection with a computer [7].     

降低发动机试验稳态压力测量不确定度方法研究

为降低系统不确定度,分析试验台稳态压力测量系统的各不确定度来源,对降低稳态压力测量系统不确定度的重要因素进行分析并提出相应改进方法。采用压力传感器现场校准方法降低测量系统与检定系统差异引入不确定度,采用三次样条插值法对压力传感器进行温度补偿降低工作环境温度对压力传感器影响引入不确定度。经验证,两种改进方法有效降低了系统的不确定度,该改进方法在其他型号发动机试验以及相关组合件试验中具有重要的推广和应用价值。     

位移传感器校验装置的研制

为解决大量程位移传感器检定过程中,传统人工手动检定法操作复杂、耗时长、测量准确度低的问题,研制了大量程位移传感器自动校验装置。详细介绍了该装置的硬件组成和软件设计,并阐述其创新特色。利用该装置对LVDT位移传感器进行校准,并对其测量不确定度进行评定。试验证明,该位移传感器校验装置测量准确度高、运行稳定性好,可有效提高检定效率,能够替代人工对位移传感器进行自动化检定,具有重要技术借鉴意义。     

高精度星敏感器二轴标定转台的设计

作为航天飞行器的姿态控制重要元件星敏感器,其控制精度的检测标定显得尤为重要,本文针对星敏感器测量空间里间角距的重要指标,提出了采用高精度二轴转台的设计方案,较好地实现了对星敏感器静、动态标定的目的,并对二轴转台的设计进行了详细的介绍．     

基于独立分量分析的六维力传感器标定矩阵的校正

为了提高六维力传感器的测量精度,提出了一种基于独立分量分析(ICA)的静态标定方法。作用在上平台的各维力经过六维力传感器后形成混合信号,该方法先对混合信号进行ICA分解,即将其分离成独立的分量,再结合理想源信号恢复出各维真实作用力的排序和幅值,最后得出校正后的标定矩阵。仿真结果表明,校正后的标定矩阵更接近标准的标定矩阵,从而提高了六维力传感器的测量精度。     

高精度电容式位移传感器校准方法的研究

介绍一种使用激光干涉仪结合单轴精密位移台对电容式位移传感器进行校准的方法。建立了一套高精度电容式位移传感器校准装置,利用单轴精密位移台位移与电压之间的关系产生纳米级的微小位移,同时使用激光干涉仪和待校准电容式位移传感器测量单轴精密位移台的微小位移。该装置可实现电容式位移传感器线性度、测量重复性以及测量分辨率的校准。实验验证了此校准方法的准确性和实用性,对影响校准的主要因素进行了分析,其综合不确定度为2.2 nm。     

基于光频梳的乙炔稳频1542 nm激光波长测量研究

利用光频梳对稳频激光波长进行测量是建立基于光频梳的波长基标准的必经程序。为了建立基于光频梳的波长标准,并为开展激光波长校准工作提供技术准备,利用自研光纤光频梳对乙炔稳频1542 nm激光波长进行了测量。利用光频梳产生参考激光与待测激光差拍,通过简单的代数关系获得了乙炔稳频激光的绝对频率和真空波长,并与相应的国际推荐值进行了对比。实测获得的乙炔稳频激光的真空波长值为1542.38 371 235 742 nm,在CIPM给定的不确定度范围内,秒稳定度为4.13×10-13。两台不同的光频梳对乙炔稳频激光波长的测量结果具有高度一致性,进一步证明了光频梳对激光波长的测量准确性。本研究对于顺应国际长度基标准发展趋势,加速光频梳在激光波长测量领域的应用进程具有重要意义。     

脉冲式动态压力溯源方法研究

动态压力测试在工业领域应用越来越广泛,而可靠的校准技术则是动态压力量值准确的保障,溯源问题一直是制约动态压力校准技术发展的瓶颈。本文以基于激光干涉的可溯源动态压力测量方法为研究对象,针对液体脉冲压力的特点,建立基于牛顿第二定律的脉冲压力测量模型,对各影响因素引入的误差进行分析和测试,通过压力传感器校准试验完成激光干涉测量可行性验证和测量不确定度分析,实现脉冲压力的可靠溯源。     

Boundary element analysis of the electromagnet casting mould

A coupled boundary element (BE)-impedance boundary condition (IBC) formulation is used to develop an electromagnetic mold design model, taking into consideration the problem of predicting the shape of the free boundary. The computational model of the electromagnetic mold consists of a right cylindrical conductor, representing the molten metal, coaxial with an induction coil, generally having a single turn, and a field shaping short circuited turn. The IBC is applied to the high-resistivity molten metal region, and the full BE formulation is used for the field shaping turn. An iterative procedure is developed to predict the shape of the molten metal free surface by satisfying the balance between the electromagnetic and gravitational pressures. Results showing the effects of the single turn confinement coil and shielding turn placement on the electromagnetic pressure distributions and on the shape of the free surface are presented     

基于长冲程振动台导轨弯曲校正的低频振动传感器校准方法

针对长冲程振动台的导轨弯曲对于基于振动台的低频振动传感器灵敏度幅值校准的影响,采用机器视觉方法测量导轨弯曲.通过建立校正模型消除导轨弯曲的影响,以提高灵敏度幅值的校准精度.导轨弯曲测量结果表明,被校振动传感器的负载越大,导轨弯曲越大,对灵敏度幅值校准的影响越大.与地球重力法的对比试验表明,在0.04 ～2 Hz范围内弯...     

基于线结构光传感器的工业机器人运动学参数标定

针对工业机器人绝对定位精度较低问题,提出一种基于线结构光传感器的工业机器人运动学参数标定方法.首先,将线结构光传感器固定安装在机器人末端,建立传感器测量模型,然后建立机器人运动学模型,通过手眼关系将传感器模型与机器人模型连接组成完整的标定系统模型.其次,使线结构光传感器在不同位姿下对某一固定点进行测量,得到该点在机器人...