Novel Fiberoptic Sensing Array and Fundamental Experiments

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Investigation of an array technique for robotic seam tracking ofweld joints

A noncontact optical preview sensing technique for possible application to a robotic seam tracking system is presented. This technique uses a structured laser illumination source: a SELFOC lens array (SLA) coupled to a fiberoptic and a phototransistor (photodetector) array. The experimental results with the SLA and fiberoptic array demonstrate the feasibility of linear fiberoptic array sensing of the weld joint. The intensity profiles acquired by the array were such that when combined with suitable data processing software routines, the sensing technique was able to provide satisfactory measurements of joint width and location of the centerline. An experiment demonstrates the viability of the approach for tracking of a weld seam. A clear profile containing the expected features was obtained at each cross-sectional location as the joint was traversed     

Neural Network Signal Processing Approach for Damage Assessment in Fiberoptic Smart Material Systems and Sructures^①②

An approach by using neural network signal processing in associate with embedded fiberoptic sensing array for the newly developed“smart material systems and structures” is discussed in this paper.The principle,structure of this approach and suitable neural network algorithms are described.The results of simulation experiments are also given.     

智能材料与结构中的光纤传感阵列及其神经网络处理

提出了一种新颖的、采用周期性对称与不对称刻纹多模光纤组成的传感阵列网络，可用于智能材料与结构的应力、应变等的状态探测或损伤估计。探索采用了人工神经网络技术处理其阵列传感信号，给出了ＢＰ网与Ｋｏｈｏｎｅｎ网的仿真结果     

光纤传感信号的神经网络处理

本文简述了光纤智能结构及系统中应用神经网络对其信号进行处理的必要性,重点对偏振光纤传感、少模光纤传感及光纤传感阵列信号的神经网络处理原理与技术进行了分析,指出了光纤传感信号引入神经网络处理的优点。     

光纤水听器阵列TDM信号处理算法研究

介绍一种用于光纤水听器阵列的时分复用（TDM）及解复用信号处理系统,该系统基于PC机,设计开发方便、使用灵活。采用Labview编写的信号处理软件可实现8单元水听器阵列的时分复用及解复用。     

纤维光学技术在通信卫星中的应用

本文介绍了纤维光学技术在通信卫星中的应用,所论应用领域包括卫星地面终端微波光纤线路、大孔径相控阵天线和卫星通信转发器。     

机敏材料中的光纤传感与信号处理技术

简述了机敏材料与结构内状态监测，损伤估计用光纤传感器，光纤传感阵列及其输出信号的人工神经网络处理原理、技术的研究进展和发展趋势     

Structural Damage Assessment by an Embedded Fiberoptic Sensor Array and Its ANN Signal Processor

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Structural Damage Assessment by an Embedded Fiberoptic Sensor Array and Tts ANN Signal Processor

A novel type of two-dimensional damage assessment system for real-time monitoring the structural health of composite strurcture is described.The configura-tion of the embedded fiberoptic sensor array and the model of the artificial neural net-work(ANN) are discussed.The experimental system and results show that the system can monitor a damage of structures with potential application in areas usch as space aero-uautics,civil engineering,etc.     

Estimation of radio refractivity structure using matched-fieldarray processing

In coastal regions the presence of the marine boundary layer can significantly affect RF propagation. The relatively high specific humidity of the underlying “marine layer” creates elevated trapping layers in the radio refractivity structure. While direct sensing techniques provide good data, they are limited in their temporal and spatial scope. There is a need for assessing the three-dimensional (3-D) time-varying refractivity structure. Previously published results indicate that matched-field processing methods hold promise for remotely sensing the refractive profile structure between an emitter and receive array. This paper is aimed at precisely quantifying the performance one can expect with matched-field processing methods for remote sensing of the refractivity structure using signal strength measurements from a single emitter to an array of radio receivers. The performance is determined via simulation and is evaluated as a function of: (1) the aperture of the receive array; (2) the refractivity profile model; and (3) the objective function used in the optimization. Refractivity profile estimation results are provided for a surface-based duct example, an elevated duct example, and a sequence of time-varying refractivity profiles. The refractivity profiles used were based on radiosonde measurements collected off the coast of southern California     

Comparison of conventional and fiberoptic manifolds for a dual band(UHF and S) phased-array antenna

We compare the weight, size, and power consumption of conventional and fiberoptic manifolds for a large dual-band (S and UHF) array antenna. The conventional manifold is based on a corporate feed comprised of coaxial cables and stripline combiner circuits. In the fiberoptic manifold, optoelectronic devices are used to convect the signals between the optical and electrical domains at the manifold interfaces, and then the signal distribution and combination are implemented with optical fiber. Both designs meet the same bandwidth, output power, and signal-to-noise ratio requirements     

联合感知矩阵优化的穿墙MIMO阵列稀疏成像方法

采用压缩感知理论的穿墙稀疏成像恢复算法需要感知矩阵满足有限等距性质(RIP),最直接的验证方法是判定感知矩阵的相干系数是否较小。针对现有的穿墙多输入多输出(MIMO)阵列稀疏成像方法没有验证感知矩阵是否满足RIP 性质而容易出现重构失败并导致成像模糊的问题,提出一种联合感知矩阵优化的穿墙MIMO阵列稀疏成像方法。该方法首先依据配置指标将阵元配置为两端发中间收和分时复用的模式,既能使感知矩阵的相干系数最小,又能获得均匀而不冗余的等效虚拟阵元;然后,从中选取部分能够满足感知矩阵相干系数最小的虚拟阵元组合,使用可分离逼近结构稀疏恢复算法充分考虑扩展目标信号的结构稀疏先验信息对其进行稀疏成像重构;最后,选取成像性能指标较好的一组作为成像结果。仿真和实验结果表明,该方法降低了运算量和虚拟阵元间的干扰,节约了硬件成本,提高了算法的稀疏重构性能,获得了高分辨的穿墙扩展目标成像。     

光纤智能结构中的光纤联接

光纤能以多种不同的构造方式集成并埋入复合材料中来构成可使用的智能结构,但如果没有有效的光纤联接技术,所有的埋入能力和传感器活动就找不到在实际可行的结构中去应用。文章作者对光纤智能结构中光纤互联问题按光纤联接的要求,光学联接法与装置、联接器件设计三方面进行了探讨。     

光纤传感器的研究及应用

介绍了光纤传感器与其他传感器相比的优点,还介绍了传感型光纤传感器与传光型光纤传感器的基本原理.同时,文章阐述了强度调制型光纤传感器、干涉型光纤传感器、光纤光栅和光纤声发射传感器的应用.文章最后提出了我国光纤传感技术存在的问题以及发展方向.     

嵌入式纳米金阵列的表面等离子共振传感特性研究

基于本征值方程及时域有限差分(FDTD)算法,研究了嵌入二氧化硅衬底的菱形纳米金阵列表面等离子共振传感特性,推导出共振模式随嵌入深度变化的关系式.计算结果与数值模拟一致,验证了金纳米颗粒阵列上下介质的不对称性可以等效为单层介质光栅.理论分析了透射谱中产生多个共振峰的物理机制与影响因素,进一步探讨了透射谱与嵌入深度、长短轴比例、周期尺寸等参数的关系,分析了阵列结构的传感性能特点,为制作多波段工作的表面等离子体共振(SPR)传感器基底提供了理论依据.     

稀疏阵列微波暗室成像实验研究

为了在实际条件下验证稀疏阵列孔径综合方法可以避免稀疏阵旁瓣较高的问题,以及基于压缩感知理论的成像算法可以对具有稀疏特性的目标进行重建,开展了微波暗室实验。针对实验中的阵列误差,给出了具体的校正方法。通过实验数据处理证明了阵列误差校正方法、稀疏阵列孔径综合方法以及基于压缩感知理论成像算法的正确性和有效性。     

基于FBG阵列的滑动探测系统设计

为了实现机械结构中夹持状态的实时监测,避免施力过大造成损坏或施力过小造成滑落,设计了一种基于FBG阵列的滑动探测系统。利用正交分布FBG阵列实现对不同方向滑动的感知,通过解算各位置上FBG波长偏移量完成对目标位置与滑动状态的分析。给出了系统结构设计及计算方法,仿真分析了不同参数的FBG对物体的滑动测试效果。仿真结果显示,采用lFBG=10 mm,h=4 mm的参数选择可以在保证空间分辨精度的基础上达到最大灵敏度。实验中,传感单元采用60 mm×40 mm×10 mm的硅胶体构成,内部预埋5个FBG构成传感阵列。实验结果显示,在x轴和y轴方向上,其灵敏度分别为0.0051 nm/N和0.0063 nm/N。FBG波长偏移量的变化曲线可以明确表征在传感模块上被测物的状态(静止、开始滑动、稳定滑动)。针对不同滑动速度进行了测试,FBG产生的波长偏移量变化所占时长与滑动时长成比例,即可通过波形完成滑动时长的解算。     

Charge transfer and blooming suppression of charge transfer photodiode area array

A charge-transfer photodiode array combines the advantages of diffused diodes for broad and smooth spectral response and analog registers for low-noise readout. The device structure described is that of a high-speed low-blooming 100-by-100 diode array using bucket-brigade readout registers. Two of the mechanisms which are essential to successful operation of this combination structure are studied. These mechanisms are the charge transfer from sensing diode to the analog register and blooming suppression. It is found that the charge-transfer speed degrades sharply with reducing light level due to subthreshold leakage behavior of the MOS transfer gate. This degradation is eliminated by using a background charge supplied from the analog register. Experimental data confirms the validity of the concept.     

P(VDF-TrFE)膜悬空结构集成热释电线列研究

用聚偏氟乙烯－三氟乙烯「Ｐ（ＶＤＦ－ＴｒＦＥ）」薄膜作１６＊１集成热释电线性阵列的敏感膜,经退火和７５ＫＶ／ｍｍ场强极化后测得其相对介电常数为１２．６,介电损耗约０．０１。为了降低热导和热容,提高探测器的探测灵敏度,用ＫＯＨ作化学腐蚀完全去除了线性阵列下方的硅衬底,形成悬空结构。