Spatial shape reconstruction using orthogonal fiber Bragg grating sensor array

With distributed orthogonal fiber Bragg grating (FBG) sensor arrays used as modular detection units, an implementation method for deformation detection and spatial shape reconstruction of a frame model structure was proposed in this paper. After brief introduction of curvature detection principle of FBG sensor, the design, fabrication and encapsulation of the FBG modular detection unit were illustrated detailedly. Every unit was composed of four optical fibers, each containing an array of FBG strain sensors. In addition, the method and procedure of the reconstruction algorithm of three dimensional spatial curve based on orthogonal curvature were also described in detail, as well as discrete curvature continuity method. The constructed algorithm was applied to reconstruction the vibration deformation of the experimental frame model, in which four FBG modular detection units were embedded. Afterward, experimental test and verification were performed for static bending and dynamic excitation of the frame model structure, using the developed experiment system. And experimental results verified the feasibility and effectiveness of deformation detection and spatial shape reconstruction based on orthogonal FBG sensor array. Moreover, the results indicated that the proposed method can provide useful research thinking for the further study of active monitoring of flexible space structures.     

Visual reconstruction of flexible structure based on fiber grating sensor array and extreme learning machine algorithm

A visual reconstruction method was proposed based on fiber Bragg grating (FBG) sensors and an intelligent algorithm, aiming to solve the problems of low accuracy and complex reconstruction process in conventional reconstruction methods of flexible structures. Firstly, the wavelength data containing structural strain information was captured by FBG sensors, together with deformation displacement information. Subsequently, a predicted model was built based on an extreme learning machine (ELM) and further optimized by the particle swarm optimization (PSO) algorithm. Different deformation patterns were tested on an aluminum alloy plate, indicating the ability of the predicted model to produce the deformation displacement for reconstruction. The experimental results show that the maximum error can be as low as 0.050 mm, which verifies that the proposed method is feasible and satisfied with the deformation monitoring of the spacecraft structure.     

高精度准分布式光纤光栅传感系统的研究

利用一个经过温度补偿封装的长周期光纤光栅解调系统中所有测量点的传感光栅的波长漂移,实现了实时、高效解调的准分布式测量.理论研究表明该系统适用于对温度、应变等参量的多布点准分布式测量.并以温度为例从实验上研究了高精度的准分布式光纤光栅传感系统.通过改善每个测量点的测量精度来提高整体系统的测量精度.利用金属槽对传感光纤布喇格光栅进行增温敏封装,使其温度灵敏系数比普通裸光栅提高了3.6倍,并利用经过温度增敏封装的光栅作为传感元件,在110℃(-50 ℃-60 ℃)的动态范围内实现了精度为0.04- ℃的多布点准分布式温度测量,理论分析与实验结果一致.     

光纤光栅传感器的解调与复用技术

光纤光栅传感器以其波长编码的独有优势适用于准分布式测量网络.文章介绍了光纤光栅传感器的解调方法,分析了其工作原理、性能和特点.提出了几种常用的光纤光栅复用方案,比较了它们的优缺点和组网规模,并指出准分布式传感网络的发展前景.     

光纤光栅传感器监测混凝土简支梁裂缝的实验研究

以结构健康监测系统为研究背景,研究了光纤布拉格光栅(FBG)传感器。对FBG的研究起步并成熟于通信领域,而对其在土木工程领域的研究尚处于发展阶段。为了进一步促进FBG传感器的发展,推广其在工程中的应用,通过在混凝土简支梁的底部布置经纤维增强复合塑料(FRP)封装的准分布式FBG传感器和未经封装的准分布式FBG传感器,研究了准分布式FBG传感器对钢筋混凝土构件裂缝出现时的有效感知及定位问题。实验结果表明可实现裂缝的大致定位,经FRP封装的FBG传感器相对于裸光纤光栅,其应变灵敏度有所下降。     

FBG传感器关于裂缝及损伤的监测应用研究

为了满足结构健康监测的需求,采用试验方法研究了准分布式光纤布喇格光栅（FBG）传感器在裂缝监测和损伤定位中的应用。以钢筋混凝土简支梁和工字型钢梁为试验对象,对梁关键部位划分单元进行多点监测,取得了其应变变化的数据,并进行了分析以实现裂缝监测和损伤定位。结果表明,准分布式FBG传感器能够较为准确地对裂缝的发生及所测区域的损伤情况实现定位。     

An FBG impact location system based on broadband light source and improved TDoA algorithm

When a structure material is damaged by impact events, the reliability and lifetime of the material will be severely affected. So impact location is considered as the prime approach for structural health and damage monitoring. In this study, a novel fiber Bragg grating (FBG) impact location system based on broadband light source is designed, aiming at the shortcoming of existing location systems based on FBG. An improved localization algorithm based on the time difference of arrival (TDoA) is proposed for impact location. According to this algorithm, the impact position can be accurately predicted without wave velocity. Impact planar location experiments are carried out for verification of the FBG impact location system and algorithm on a400 mm×400 mm×3 mm aluminum alloy plate. The resulted locating error shows high precision and good stability of the proposed system. This work has been supported by the National Natural Science Foundation of China (Nos.61503218, 61403233, 61573226 and 61473176), the Excellent Young and Middle-Aged Scientist Award Grant of Shandong Province of China (No.BS2013DX018), and the Natural Science Foundation of Shandong Province for Outstanding Young Talents (No.ZR2015JL021). E-mail:pangdan@163.com      

机器人柔性触手形状的光纤传感及重构方法

为了解决机器人与外界交互时形状感知的需求,本文提出了一种基于FBG的用于解决机器人触手形状感知的方法。采用无粘结剂的形式将光纤光栅植入柔性硅胶片中固定,当柔性硅胶片紧贴所测物体表面时,硅胶片发生的形状变化将带动植入光纤的形状变化。通过光纤波长漂移量和弯曲曲率的关系,结合曲面重构算法构建出所测物体的表面形状,同时对柔性传感器的灵敏度进行了分析。实验证明了形状感知系统的可行性及稳定性,其灵敏度为65.822 pm/m-1,空间分辨率为3 cm,测量误差在2.9 %左右。该传感器结构简单,抗干扰性能良好,可通过改变光纤植入的深度及光栅之间的距离调节其灵敏度和空间分辨率以适应不同的情景,为执行机器人触手形状感知提供了参考。     

啁啾光栅解调的准分布式光纤Bragg光栅传感器

为了提高光纤Bragg光栅(FBG)的应用范围.提出一种线性啁啾光栅(CFBG)解调的准分布式FBG传感系统.利用波导理论分析了CFBG特性;利用传输矩阵法推导了CFBG反射谱模型及波长与相位延迟的关系,并给出了相位延迟曲线.实验表明:所设计的系统应变测量范围为0～2000 με,温度测最范围为0～80℃;相位变化与被...     

基于改进遗传算法双重约束的FBG应变分布重构研究

光纤布拉格光栅(FBG)已广泛应用于应变参数测量中,但非均匀应变易引起FBG光谱变形而无法进行波长检测,因此需重构沿FBG的应变分布。针对应变分布重构效果差且收敛速度慢的难题,在深入研究改进遗传算法的基础上,提出基于FBG光谱中心波长位置与反射率双重约束的应变分布重构理论,显著改善了重构的非唯一性和置信度。同时,假设应变分布为多项式形式,通过对多项式系数的重构实现应变分布的重构,大大提高了重构的速度。在此基础上开展了应变分布参数重构仿真实验,多项式系数重构误差均小于1.5%;结合两端固定压杆调谐光纤光栅实验,验证了该应变分布重构方法的有效性、适用性和可操作性,形成了一种快速有效的应变分布重构方法。     

Shape reconstruction based on FBG flexible sensor

In this paper, the shape of the object is reconstructed based on the fiber Bragg grating (FBG) flexible sensor encapsulated by polydimethylsiloxane (PDMS) material, and the influence of the number and layout of the sensors on the reconstruction accuracy of the object is studied. The COMSOL simulation software is used to verify the accuracy of the algorithm, and four sensors are prepared to measure and reconstruct the bent aluminum plate under set conditions. The maximum relative error of the shape reconstruction span is 1.203%, and the maximum relative error of the height is 2.802%. The research results provide the application basis for the shape detection of soft robots.     

引入曲率与角度校正的柔性机构三维形状多芯光纤重构方法

为提高柔性机构三维位形参数光纤测量精度,提出了基于曲率与角度校正的多芯光纤三维形状重构方法。通过引入方向角和曲率校正系数,改进了柔性三维形变多芯光纤重构算法;利用准分子激光器和相位掩膜法制备了多芯光纤光栅传感阵列,建立了多芯光纤三维形状重构实验系统;实验测量了不同曲率比例因子下的形状重构误差,分析了曲率与角度校正前后形状重构误差;通过对应变进行了三次样条插值,并对方向角和曲率进行了校正,得到了形状重构误差平均值为0.74 mm、最大值为1.64 mm;利用校正后的多芯光纤传感系统进行三维螺旋形变重构实验,得出重构精度提高了10.2%。研究结果表明,基于曲率与角度校正的多芯光纤三维形状重构方法具有更高精度,在柔性机构三维位形实时监测中具有应用前景。     

基于轴向应变误差修正的FBG形状重构算法

针对轴向应变误差影响光纤布拉格光栅(FBG)形状传感器的重构精度问题,提出了一种基于轴向应变误差修正的形状重构算法。纤芯位置偏差是造成轴向应变误差的主要因素,为了获取光纤形状传感器的纤芯位置偏差,提出了三芯光纤形状传感器的误差理论模型。通过ANSYS Workbench对误差理论模型进行有限元建模仿真,将纤芯位置偏差和标定偏差代入误差理论模型,对存在位置偏差的纤芯轴向应变数据进行修正,并与理想纤芯位置处的轴向应变数据进行对比,证明了该理论模型对存在误差的轴向应变数据具有良好的修正效果。为了计算每个检测点的纤芯位置偏差,根据提出的误差理论模型,提出了一种基于二分法逐次逼近的FBG形状传感器纤芯位置偏差计算方法。仿真结果表明,纤芯位置偏差修正前后重构曲线的最大位置误差从1.74 mm减小到0.10 mm。对于自封装的FBG形状传感器,使用纤芯位置偏差修正前后,重构空间曲线的最大位置误差从19.81 mm减小到7.66 mm。     

基于改进正交匹配追踪的FBG传感信号处理方法

针对光纤布拉格光栅(FBG)传感信号易受外界噪声干扰从而导致信号丢失的问题,提出了一种改进型正交匹配追踪(OMP)算法。围绕FBG传感信号波长随应力漂移的本质特征,在压缩感知理论的框架下,通过去除稀疏系数中的虚部,并利用指数饱和法对非零元素进行拟合与排序,从而获取FBG信号的有效稀疏度。在此基础上,通过改进经典OMP算法迭代过程中的原子选择策略与终止条件,有效降低算法复杂度并提高信号的重构精度。对比实验结果表明,所提出的算法在时间复杂度、信噪比与信号重构精度等方面均具有突出的优势。     

A Fiber-Optical Intrusion Alarm System Based on Quasi-Distributed Fiber Bragg Grating Sensors

A fiber-optical intrusion alarm system based on quasi-distributed fiber Bragg grating （FBG） sensors is demonstrated in this paper. The algorithms of empirical mode decomposition （EMD） and wavelet packet characteristic entropy are adopted to determine the intrusion location. The intrusion alarm software based on the Labview is developed, and it is also proved by the experiments. The results show that such a fiber-optical intrusion alarm system can offer the automatic intrusion alarm in real-time.     

基于扫描激光器和光放大的100 km光纤布拉格光栅传感系统

提出了对基于扫描激光器的光纤布拉格光栅(FBG)传感系统进行掺铒光纤(EDF)/双波拉曼混合放大的方法,大幅度提高了该光纤布拉格光栅传感系统的传输距离。该方法以高功率扫描激光器作为光源,采用双波长拉曼放大的方法对信号进行低噪声双向放大,再利用系统中间的两段掺铒光纤,将剩余的拉曼抽运功率用来产生自发辐射光和放大传感信号,使得整个系统能在超长的传感距离上获得良好的信噪比(SNR)。实验表明使用一台扫描激光传感分析仪、一只170mW的拉曼抽运和一只2W的拉曼抽运,可以使传感距离达到100km以上,并且传感系统的光纤布拉格光栅反射信号均能获得超过7dB的良好信噪比,从而实现在超长距离上的光纤布拉格光栅传感。     

基于应变模态振型和误差补偿的形状重构方法

形状传感技术是近年来传感领域备受关注的新研究方向,具有广阔的应用前景。文章提出了一种基于应变模态振型和误差补偿的形状重构方法,通过测量物体部分位置点的应变数据,采用模态理论实现应变-位移转换,进而重构物体形状。以长宽高分别为1000,1000和0.5mm的钛合金板作为研究对象,通过ANSYS workbench18有限元仿真软件获取位移模态振型及应变模态振型,依据有限元仿真中位置点模态的相似性,采用K-means++聚类算法对应变测量点位置进行优化,在合金板上表面施加400N的力使其产生形变。该算法的形状重构误差小于常规的均匀分布算法。采用径向基函数神经网络对误差和重构位移数据集进行了训练,依据拟合重构误差和重构位移的关系,补偿误差后重构误差不大于3.5%。     

基于WOA的FBG形状传感器铺设角度偏差自矫正模型

FBG形状传感器的铺设角度偏差导致曲率和挠率测量误差，进而影响形状传感器的重构精度。针对该问题，文章提出了一种基于鲸鱼优化算法(Whale Optimization Algorithm, WOA)的FBG铺设角度偏差自矫正模型。重构实验验证了所提方法的有效性，不同形状的远端重构误差分别从11.66和22.6 mm降低至5.63和10.47 mm,相对误差分别从2.56%和4.96%降低至1.21%和2.25%,相对误差从2.56%和4.96%降低至0.95%和2.06%。     

利用图像区域自然尺度特征的海面舰船目标检测

为了提高动态海面背景中目标的检测性能,提出了一种新的基于图像区域自然尺度特征的海面舰船目标检测算法.算法将一维信号的自然尺度特征提取方法拓展到二维图像信号,通过相空间重构和分类,提取了图像灰度时间序列的自然尺度特征.利用BP神经网络,得到背景与目标自然尺度特征的辨识模型,然后对图像序列的自然尺度进行分类,检测得到舰船目...     

光纤光栅脉搏波分析处理及特征提取

本文提出了一种利用光纤光栅（Fiber Bragg Grating, FBG）检测脉搏波的信号处理及特征提取算法。将光纤光栅采集脉搏波与光电容积（Photoplethysmography, PPG）脉搏波进行对比,分析出光纤光栅脉搏波的特点。提出了小波阈值消噪与改进的数学形态学滤波相结合的光纤光栅脉搏波消噪算法,并根据脉搏周期对形态学结构元素长度进行自适应选择,从而改善了去除基线漂移的效果。研究了脉搏特征提取方法,提高了脉搏波峰值点和起点检测的准确性。实验结果表明,经消噪处理后,输出脉搏波的信噪比是输入脉搏波信噪比的2倍,脉搏波峰值点和起点提取准确率分别达到了97.2%和97.6%。该算法结构简单,易于实现,对光纤光栅脉搏波检测智能服装的研发和脉搏特征的有效提取具有重要的意义。