基于FPGA的嵌入式FBG解调系统的研究

波分复用技术是构成各种复杂和大型FBG传感网络最关键的复用技术.为了有效解调FBG传感阵列,提出并实现了一种基于COMS图像传感器的FBG图像解调方案,方案的硬件平台采用以FPGA和ARM处理器为核心的主从结构设计,将FBG阵列的波长解调转化为了FBG光斑图像解调.实验结果表明,FBG图像解调系统具有精度高、复用能力强、远程监控、易于维护和升级等优点,对推广应用大型FBG传感网络有实际意义.     

面向井下环境参量的光纤传感物联网系统

为了能够大范围准确获取井下环境参量并有效抑制噪声, 研究了基于新型光纤光栅(FBG)封装的光纤传感物联网系统。设计了一种可同时测试应变与温度的传感模块, 试制了新型FBG封装结构, 搭建了符合巷道结构的光纤应力监测分布网络。采用基于互相关差分计算的方法实现了对振动噪声的消除, 并对井下巷道的应力和温度进行了连续监测。结果表明, 拱段45°与60°的FBG可以准确记录应力、温度变化数据。该系统在大范围井下环境参量监测中具有更高的稳定性、更好的适应性。     

面向光接入网的光纤光栅传感数据数字化系统

利用现有的光纤通信网实现对光纤光栅传感网络的远程监控,既可以避免重新铺设传感信道,节约成本,又可以增加传感网组网的灵活性。提出了一种基于阵列波导光栅(AWG)的面向光接入网的光纤布拉格光栅(FBG)传感网传感数据数字化系统,系统能够快速实现对携带传感信息的FBG反射波长的数字化。分析了系统的工作原理及主要误差来源,并设计了传感数据成帧模块的结构及适于在光接入网中传输的传感数据帧结构。采用OptiSystem/Matlab协同仿真的方法对一个3×3光纤光栅传感网络进行了仿真实验,实现了在-50℃～100℃范围内精度为1℃的温度监测,能够满足日常温度监控需要。实验结果表明了该方案的可行性。     

基于光纤布拉格光栅的准分布式高温监测系统

光纤布拉格光栅(FBG)具有复用能力强、灵敏度高、体积小、耐腐蚀等优点,广泛应用于多种工程监测中.使用193 nm准分子激光器在标准通信单模光纤(康宁,SMF-28)上制备了高反射率FBG阵列,并对其进行了约两个月的长期退火实验研究;设计了一种光纤高温传感系统,可在400 ℃以下对环境的温度进行准分布式测量,测温误差小...     

基于衍射解调的新型光纤光栅高温传感网络

基于光纤布拉格光栅(FBG)高温传感特性,设计了一种基于波长调制的耐高温光纤光栅传感网络。系统设计了新型封装结构的耐高温光栅传感头。并针对传统FBG传感网络结构可靠性低的缺点,设计了一种高可靠分布式传感网络结构。采用InGaAs图像传感衍射解调技术对光反射波长进行解调。20～290℃范围测试实验表明,所设计的传感网络温度响应曲线平均线性度达0.9991,灵敏度为0.0258nm/℃,测量精度达±0.6℃,响应时间小于16s,稳定性高,适用于实际工作环境中的高温测量。     

光纤光栅传感网络的优化研究

光纤光栅传感网络在大型复杂结构健康监测中具有广泛的应用前景,对光纤光栅传感网络优化的研究具有重要的意义。分析了结构健康监测中光纤传感网络优化布局和可靠性的研究现状,对光纤传感网络优化中的传感器优化布局与光纤传感网络可靠性两方面进行研究。通过对结构响应特性研究,提出了对结构静力响应参数监测时,传感器布局的一般规则。将概率计算引入光纤 FBG 传感网络不同拓扑结构,给出了基于不同拓扑结构的光纤传感网络形式及其可靠性数值分析。     

OPM在光纤传感中的应用

光纤传感随着光通信技术的成熟而得到快速发展,成为传感领域的主要方向之一,其中利用光纤布拉格光栅(FBG)的波长漂移检测环境变量的技术日趋完善.而对波长的检测,采用光性能监测模块(OPM)是一种行之有效的手段.OPM具有对光波长及波长漂移监测精确、体积小和可靠性高等特点.文章作者系统地阐述了FBG的工作原理和OPM的技术特点,并将两者组合搭建成传感测试平台.     

光纤感知阵列在线滑觉测试系统

针对智能柔性滑觉传感中位置与速度的实时监测问题,设计了一种监测目标位移与速度的光纤感知模块。首先,采用温度补偿模块解决温度交叉敏感问题;然后,在分析传感单元应力分布仿真结果的基础上提出了“米”型FBG组网结构;最后,采用标准压力计与小球完成了位置方向与速度状态的测试,并提出了适用该结构的目标状态解算模型。仿真结果显示,目标轨迹平均形变量约为0.32 μm,衰减距离宽度约为3.0 mm。实验针对0.255 kg钢制小球进行滑动测试,FBG应力灵敏度均优于0.0206 nm/N,FBG中心波长偏移量可以准确确定物体所在区域位置和物体运动方向。传感模块能够实时监测物体运动状态,智能调整物体施力大小及位姿。结果显示,该滑觉感知系统的平面定位精度、运动角度与速度换算均符合设计要求。并且根据模型函数关系可知,在调整传感网络中 FBG总量时可以实现对位置、角度及速度精度的控制。综上所述,该系统具有对检测区域内目标位置、运动状态实时监测的能力,适用于柔性智能装配、智能仿生皮肤等技术领域。     

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。     

布拉格光纤光栅及其在火箭状态监测中的应用探讨

针对火箭状态监测系统中需监测的状态参数多、测量点分布广、抗电磁辐射要求高等特点，探讨了采用布拉格光纤光栅传感器(FBG)构成全光纤型、多参数、分布式传感网络的可行性，给出了FBG传感网络中的光信号发射、传感以及信号解调与数据处理等模块的具体构成。分析了目前FBG用于火箭状态监测中存在的问题及解决途径。     

基于EPON的分布式光纤光栅传感网络研究

提出了一种基于以太无源光网络(EPON)的光纤布拉格光栅(FBG)传感网络多传感通道切换控制方案。控制传感通道切换的多个光开关分别与EPON系统中的多个光网络单元(ONU)相连,利用各ONU间严格的时间同步特性在各ONU控制下实施对多个光开关的同步切换控制,实现各FBG传感通道与传感解调模块间的有序连通。实验结果表明,此方案的稳定性较好,并且具有较灵活的扩展特性。     

Design and experimental study on FBG hoop-strain sensor in pipeline monitoring

Pipeline monitoring is an important task for the economic and safe operation of pipelines as well as for loss prevention and environmental protection. The circumferential strain is of significance in pipeline integrity monitoring. In this paper, an indirect pipeline corrosion monitoring method based on the circumferential strain measurement is firstly proposed, with main objectives at designing a circumferential strain measuring device. Combined with unique advantages of optical fiber sensing, an FBG hoop-strain sensor was designed and encapsulated. Its enhanced sensitivity mechanism in the circumferential strain measurement and manufacturing technique is detailed. The experimental study of the developed FBG hoop-strain sensor is conducted on a PVC model pipeline to investigate its characteristics, including reliability and some tentative dynamic tests. Results of model tests show that the FBG hoop-strain sensor demonstrates good performance in the circumferential strain measurement, and can be considered as a practical device for pipeline health monitoring.     

Performance Optimization Based on Compressive Sensing for Wireless Sensor Networks

A routing algorithm, based on a dual cluster head redundant mechanism combined with compressive sensing data fusion algorithm, is proposed to improve reliability and reduce data redundancy of the industrial wireless sensor networks. The Dual cluster head alternation mechanism is adopted to balance the energy consumption of cluster head nodes. Through the compressive sensing data fusion technology to eliminate redundancy, effectively improve the network throughput of the sensor network. The simulation results show that the proposed algorithm is able to enhance the networks performance, significantly reduces the number of lost packets and extend the network’s lifetime.     

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.     

Hypervelocity impact monitoring and location identification on aluminum plate based on FBG sensing system

To achieve the real-time detecting and localization of hypervelocity impact events, a monitoring and localization system was designed based on fiber Bragg grating (FBG) sensor network. First, the simulation model was built to study the damage evolution and wave propagation process. Subsequently, based on the response mechanism of FBG to strain, the corresponding high frequency demodulation system was designed. Furthermore, a hypervelocity impact experiment was performed to verify the effectiveness of the designed system. Finally, combined with the diamond sensor array localization algorithm, the accurate position of hypervelocity impact source can be achieved.