深水水位检测用压力传感器补偿方法研究

针对压力传感器受温度影响后产生零点漂移和灵敏度漂移的问题,提出了一种基于曲线拟合与插值算法相结合的自动校正方法,比对了该方法对压力传感器的灵敏度误差、温度漂移和零点漂移进行补偿所取得的效果。测试结果证明:该方法可有效提高传感器的抗干扰能力与工作效率。配以自行设计的上位机显示界面,使整套开发系统兼备可视化与实时性。     

MEMS差动电容加速度传感器

介绍了一种MEMS差动电容加速度传感器的设计及所达到的技术指标。对MEMS Sensor选择差动电容传感器的理论依据进行了分析，叙述了MEMS差动电容加速度传感器各项参数的设计依据，包括灵敏度、非线性、温度漂移、隔离度、频带宽度等，同时介绍了该传感器各项指标的测试数据。该传感器具有灵敏度高、参数设计合理，不用温度和线性补偿就达到了高线性和低漂移，结构合理，达到理想的横向隔离效果和宽的频率响应特性等特点。     

压阻式冲击硅微机械加速度传感器的温度补偿

给出了一种压阻式冲击硅微机械加速度传感器的温度补偿与实现方法.该方法采用串并联电阻来补偿加速度传感器的零位温度漂移,采用在电源后串联二极管来补偿加速度传感器的灵敏度温度漂移.具体实现时,采用高低温试验机对加速度传感器的环境温度进行变化,通过检测系统测量出4个压敏电阻在高低温时的电阻值,运用软件计算出补偿电阻值、补偿电阻在桥路中的位置以及串联二极管的数量,并根据计算结果构建出了带温度补偿的传感器检测电路.测试结果表明,这一方法能有效补偿加速度传感器的温度漂移.     

基于最小二乘法的电化学传感器温漂补偿研究

现有的电化学氢气传感器其温度特性不太理想,传感器输出的灵敏度与零点值随温度的变化发生漂移,测量精度不高,误差较大,因此需对其进行温度漂移补偿[1-4]。基于最小二乘法改进了一种多项式曲线拟合方法,通过一定的条件约束和工程估算,得到一种温度漂移补偿算法[5]。利用该算法对不同温度下的实测数据进行处理,极大改善了环境温度变化对系统输出的影响,通过理论数据和实测数据验证了算法的有效性和可行性,并用于工程实践。     

基于三次样条曲线插值的压力传感器温度补偿研究

压阻式压力传感器受半导体温度特性的影响,易产生热零点漂移和热灵敏度漂移,这是影响传感器性能的主要因素。现介绍了采用三次样条曲线插值方法对压阻式压力传感器热零点漂移和热灵敏度漂移进行补偿修正的方法,通过试验验证了三次样条曲线插值补偿方法对压力传感器热零点漂移和热灵敏度漂移的补偿效果。该方法对于解决高精度压力传感器的温度补偿问题具有较高的推广应用价值。     

压阻式压力传感器温度误差的数字补偿技术

压力传感器性能易受温度变化的影响,产生零点温度漂移和灵敏度温度漂移,从而增加了测量结果的误差.根据压阻式压力传感器温度误差分析,提出了基于MAX1457芯片的数字补偿技术,对温度误差进行补偿,并运用到多个压阻式压力传感器上,在特定的温度允许下进行补偿.结果表明该种方法补偿精度高、稳定性好,有效地抑制了温度漂移.     

逆磁致伸缩扭矩传感器温度漂移特性研究

温度漂移是影响逆磁致伸缩扭矩传感器灵敏度和测量精度的主要因素之一，为消除温度漂移的影响，设计了一种桥式电路并分析了输出信号的特性。实验表明：当受温度影响时，其输出信号由扭矩分量和温度影响分量组成，每个分量都具有稳定的相位角，通过相位差关系从输出信号中除去温度分量，就可以消除温度的影响。结果表明：传感器的温度漂移得到了很好地控制，在全刻度范围内小于1％／50℃，能够满足扭矩工程测量的要求。     

基于温度补偿方法去敏的新型光纤光栅压力传感器

本文阐述了一种带温度补偿、基于平面薄板结构的新型光纤光栅压力传感器.作为弹性体的压力敏感薄板,其硬心通过一L型刚性位移传递机构拉动压力敏感FBG;温度去敏通过被动温度补偿和残留温度效应实时修正来解决.传感器性能指标测试如下:重复性0.066%FS,回程误差0.846%FS,线性度0.102%FS,传感器精度±0.591%FS;在-30℃到+80℃范围内,传感器零点漂移为+1.720 8%FS,灵敏度漂移为+0.010 4%FS,传感器温漂为+1.731 2%FS.     

电磁力平衡传感器的磁缸温度稳定控制方法研究

未温度补偿过的电磁力平衡传感器温度漂移达200×10-6 g/℃,远不能满足万分之一克及以上的电子分析天平计量性能要求。详细分析了电磁力平衡传感器磁缸温度变化对传感器输出的影响,根据传感器结构及热传递路径,设计了一种基于高精度数字温度传感器的温度检测模块;利用正弦波信号在线圈上做功发热但产生电磁力合力为零的特点,提出了一种基于脉冲宽度调制(pulse width modulation,PWM)控制的电磁力平衡传感器磁缸温度稳定控制方法。该方法根据磁缸温度变化量以及加载物体质量大小,不断地调节PWM输出的占空比,控制正弦波信号导通时间,改变线圈的发热量,实时调节磁缸的热平衡。实验研究表明,基于电磁力平衡传感器的电子分析天平应用上述研究方法后,温度漂移降低至15×10-6 g/℃,有效地改善了传感器温度稳定性,大大降低了天平温度漂移补偿的难度。     

汽车检测用钳形电流传感器的设计

针对汽车检测系统的需求,设计出了一种车用钳形电流传感器,该传感器线性度和稳定性高、位置误差和温度漂移小、抗干扰能力强.该传感器可广泛地应用于军用车辆和民用车辆的带电维修检测.文中介绍了该钳形电流传感器的工作原理和设计制作过程.     

涡流阵列检测裂纹特征提取方法的研究

涡流阵列检测是一种可以对大面积平板和复杂形状关键件实施快速、有效检测的电磁无损检测技术.在简要阐述涡流阵列检测技术原理的基础上,设计制作了涡流阵列检测平台和涡流阵列传感器.基于涡流阵列6种激励检测模式,提出了裂纹长度和深度定量检测的方法.研究结果表明:裂纹长度可通过小波变换提取锁定放大输出幅值波形的特征点如波峰、波谷、拐点等的位置准确计算,裂纹深度可通过弹性BP神经网络对输出幅值波形波峰峰值的训练来较为准确地估计.     

基于虚拟示波器的涡流应力测量装置研制

为将涡流阻抗法应用于金属构件应力的快速测量,基于改进的矢量伏安法,采用虚拟示波器技术,研制出一套测量参数可控的便携式阻抗测量装置。实验测试了信号平均次数、电路采样电阻等对涡流传感器阻抗-频率特性曲线测量精度的影响规律,在优化参数条件下,研制的阻抗测量装置与Agilent 4294a的测试结果较为一致,相对偏差在±5%范围。将便携式装置应用于金属杆件的涡流应力测量:先后对45号钢杆和LY12铝合金直杆进行拉伸实验,测量粘贴于直杆上涡流传感器的阻抗变化,回归分析得到阻抗变化率与拉力的直线拟合方程(拟合优度大于0.9)。实验结果表明,基于虚拟示波器的阻抗测量装置可以基于涡流测力原理,实现金属构件应力的快速、有效测量。     

电磁流量计干标定技术

介绍电磁流量计干标定技术的研究现状及工业化应用前景,阐述电磁流量计干标定原理.指出如何准确测量有效区域内各点磁场信息是电磁流量计干标定技术工业化应用的关键技术,利用电磁流量计磁场的交变特性,通过测量电磁感应所产生的其他物理量间接获取电磁流量计有效区域内磁场信息,是解决此关键技术的有效途径,并以此为基础重点分析了涡电场测量法与面权重函数法这两种新型干标定方法的测量原理、特点及实现方法.此项技术为我国开展电磁流量计干标定技术的研究及工业应用提供技术参考.     

Investigation of the magnetic field response from eddy current inspection of defects

Eddy current testing is one of the most widely used methods in non-destructive testing for the inspection of conductive materials. Numerical modelling of eddy current testing has emerged as an important approach alongside experimental studies. This paper investigates an application of numerical modelling and experimental study as a means of the quantitative non-destructive evaluation (QNDE) of defects in conductive samples. There are two methods of measuring eddy current response, more commonly by measuring the change in impedance of the eddy current probe coil, or as used in this work, by measuring the change in magnetic field directly using magnetic field sensors such as superconducting quantum interference devices, giant magneto resistance, or as in this case Hall sensors. Specifically, measurements made using an eddy current probe containing an excitation coil and a Hall sensor, experimentally obtained using an X?CY scanner table, are compared with a numerical (finite element method) model. The discrepancies between the experimental tests and the numerical models have been analysed and explained, which is an important factor in engineering applications of QNDE.     

Modeling of eddy current sensor using geometric and electromagnetic data

In this paper a new modeling method for an eddy current sensor is presented using geometric and electromagnetic data of a sensor and a measuring target It can predict not only sensor output but also medium behavior related to sensor output The geometric data of a sensor coil and the eddy current generated on a measuring target are simplified to an array of circular loops. And to perform computations of the network circuit between sensor coil loops and eddy current loops using the geometric and electromagnetic data in order to consider all possible interactions, the equivalent network circuit of eddy current sensor’s behavior has been drawn. Because the sensor’s initial value, medium behavior, and final value can be shown quantitatively by the proposed modeling method as the geometric and electromagnetic data varies, it can precisely predict the sensor output depending on the measuring goal and application field. Thus the model can be utilized to improve accuracy, eliminate the need for calibration before use, and produce the best design for any given purpose.     

地下电缆排管涡流损耗及经济性分析

为解决传输线电流在传统钢筋混凝土地下电缆排管中产生涡流损耗而造成电能浪费的问题,将有限元数值分析技术应用于地下复杂环境涡流-温度场的分析和计算。提出了地下电缆排管涡流-温度耦合场的三维有限元模型,兼顾求解速度和计算精度需求的剖分方法以及多物理耦合场的迭代求解方法。通过对典型钢筋混凝土结构地下电缆排管的涡流场和温度场的数值分析,得到了典型钢筋混凝土结构地下电缆排管中金属构件的涡流分布,整个场域的温度场分布和谐态工况下的电缆线芯的温度;并据此提出了玻璃纤维代替传统钢筋的解决方案,对比分析了两种结构电缆排管的技术特点和经济性能。数值分析结果表明,使用玻璃纤维筋电缆排管的替代方案在能够降低涡流损耗的同时具有更好的经济效益。     

Measurement of Electromagnetic Parameters of Metal-Coating Thickness Measures

Thickness measures for electrically conductive coatings applied to electrically conductive bases are described, for which not only geometrical but also electrophysical parameters such as the specific electrical conductivity and complex relative permeability of the measure base and the specific electrical conductivity of the measure coating are prescribed. The procedure and a technique for measuring the specific electrical conductivity of the base of a measure using the van der Pauw method, the complex relative magnetic permeability of metal on ring-shaped samples using a permeameter, a technique for transferring the value of this parameter to the measure base of an arbitrary shape with a flat surface, and also the procedure and a method for measuring the specific electrical conductivity of the coating-measure material with the use of an eddy current probe with a wave-like drive winding are described.     

源于温度的电涡流传感器交叉敏感的补偿

文中在分析了高温差环境造成电涡流传感器交叉敏感的机理的基础上,以电涡流传感器在测量液态金属的电阻率过程中所出现的问题为例,提出了若干相应的补偿措施。     

Development of eddy current microscopy for high resolution electrical conductivity imaging using atomic force microscopy

We present a high resolution electrical conductivity imaging technique based on the principles of eddy current and atomic force microscopy (AFM). An electromagnetic coil is used to generate eddy currents in an electrically conducting material. The eddy currents generated in the conducting sample are detected and measured with a magnetic tip attached to a flexible cantilever of an AFM. The eddy current generation and its interaction with the magnetic tip cantilever are theoretically modeled using monopole approximation. The model is used to estimate the eddy current force between the magnetic tip and the electrically conducting sample. The theoretical model is also used to choose a magnetic tip-cantilever system with appropriate magnetic field and spring constant to facilitate the design of a high resolution electrical conductivity imaging system. The force between the tip and the sample due to eddy currents is measured as a function of the separation distance and compared to the model in a single crystal copper. Images of electrical conductivity variations in a polycrystalline dual phase titanium alloy (Ti-6Al-4V) sample are obtained by scanning the magnetic tip-cantilever held at a standoff distance from the sample surface. The contrast in the image is explained based on the electrical conductivity and eddy current force between the magnetic tip and the sample. The spatial resolution of the eddy current imaging system is determined by imaging carbon nanofibers in a polymer matrix. The advantages, limitations, and applications of the technique are discussed.