基于FPGA和以太网接口的光栅解调应用

光纤光栅的传感信息是采用波长编码的方式进行的,解调的关键就是把传感信息从波长编码中完整地解调出来.文中介绍的光栅解调系统采用F-P滤波器对ASE光源进行扫描;采用FPGA作为控制核心;采用DM9000A完成网络接口设计,在FPGA内部实现了对光栅传感信号质心解调算法的程序设计和以太网接口控制程序的设计,FPGA具有多通道高速同步解算的能力,在对F-P滤波器500 Hz的扫描速率下,很好地实现了光纤光栅波长的同步实时解算.解调系统的解调精度可达到2 pm左右.     

浮空器柔性复合蒙皮变形光纤光栅传感方法

针对浮空器气囊蒙皮变形的实时监测需求,提出了基于光纤光栅（fiber Bragg grating, 简称FBG）的柔性复合蒙皮变形传感方法。根据蒙皮材料的多层结构特点及光纤光栅传感原理,设计了“光纤光栅?粘贴层?基体”的柔性蒙皮传感结构。通过对传感结构进行理论分析,得知平均应变传递效率随粘贴层剪切模量增加而增大。实验采用GD414和DP420两种不同剪切模量的粘接剂将光纤传感器粘接在柔性蒙皮表面,建立了传感解调实验系统。分析了浮空器柔性复合蒙皮变形光纤光栅传感器灵敏度及重复性,研究了两种不同胶接剂封装下光纤光栅中心波长随曲率变化的关系,结果显示剪切模量较大的DP420胶接剂封装的FBG具有良好的线性度和重复性,其灵敏度可达145.4 pm/m-1。对浮空器柔性复合蒙皮变形进行重构分析,验证了传感方法的可行性。研究结果表明,光纤光栅传感器可用于柔性复合蒙皮变形监测,在浮空器气囊蒙皮形态监测中具有广阔的应用前景。     

柔性曲面变形检测的FBG方法

为实现太阳能帆板、飞机机翼等薄板类曲面的动态检测,构建了一种基于光纤光栅（FBG）的传感阵列系统。将FBG传感器分布式地封装在形状记忆合金（SMA）薄片上,并采用增加预应力方式,扩大FBG检测拉应力的检测范围;利用空分复用（SDM）和波分复用技术（WDM）将FBG阵列布置到曲面上,传感器分布根据曲面应力状况采用植入式分布,应变较大的地方布置稠密,反之稀疏;曲面发生变形时,解调仪器解调出波长变化;计算机对采集数据进行处理,重建曲面形状并实时显示,以实现曲面的动态检测和显示。实验结果表明,此传感阵列系统的波长变化与曲率具有较好的线性关系,传感器布置合理、测量精度高,利用FBG能够实现曲面变形检测。     

光纤光栅温湿度检测系统研究

为了实现对室内环境的温度和湿度的实时监测,设计了一种光纤光栅温湿度检测系统。该系统以光纤光栅传感器为温度和湿度检测的敏感元件,利用波分复用技术对光纤光栅传感器进行传感网络的组建,利用F-P腔解调原理对光纤光栅传感器进行波长的解调,采用LabVIEW编写光纤光栅温湿度系统的上位机软件。光纤光栅温湿度检测系统解决了传统电力系统的组网困难,电缆质量重,测量误差大,易受电磁干扰等问题,实现实时监测环境的温湿度和数据的保存,适合各种室内环境的温湿度监测的场合。     

光纤光栅传感系统数据采集与处理技术

在光纤光栅传感系统中,运用多通道智能光纤光栅解调器采集传感信号,并采用TCP/IP协议采集光纤光栅解调器各通道的光谱数据,经过峰值检测和温度补偿后,根据传感器的标定数据换算出对应各监测点的物理量,较好地实现了光纤光栅传感系统的数据采集与处理.并在光纤光栅反射波形的峰值检测技术中引进了指数平移钝化算法替代计算复杂度较高的高斯拟合算法,能有效地减少各种干扰因素引起的峰值波长抖动.     

基于FPGA的千兆UDP/IP协议栈的实现及其在高速图像传输中的应用

设计在FPGA中实现了一套简化的千兆以太网UDP/IP协议栈,协议完全兼容IEEE802.3a千兆以太网标准,解决千兆以太网IP核移植性差和消耗FPGA资源量大的问题;设计FPGA采集CMOS摄像头图像数据的接口;利用UDP/IP协议栈完成采集的实时60f/s图像的传输;在wireshark上抓取图像数据,实验结果表明,该高速图像传输接口能够满足高速图像传输的设计预期。     

基于FPGA的光纤布拉格光栅解调系统设计

设计一种基于FPGA数据采集模块的光纤布拉格光栅解调系统以提高其高速实时性。系统采用VB编程PC控制,首先调控扫描可调谐激光光源,使之在可调谐波长范围内实现快速波长调谐、高精度任意波长点锁定、高稳定度功率输出;再对采集的数据进行解调解读并实现解调过程的可视化显示。试验结果表明,所设计系统具有良好的高速实时性,能够实现传统的基于时域解调的系统无法完成的任务,较好地解决FBG传感器空间定位等问题,可为光纤光栅解调系统在实际应用中的发展和推广提供借鉴。     

基于可调谐F-P滤波器的光纤光栅传感解调系统寻峰算法对比分析

设计出一种基于可调谐F-P滤波器的光纤布拉格光栅(Fiber Bragg Grating,FBG)传感解调数据采集与处理系统.为了尽可能提高光纤光栅传感器的精度,分别采用质心法、三次样条插值法、最小二乘法、高斯多项式拟合法等对数据采集系统获取的原始信号数据进行光纤光栅波长寻峰算法研究,并分别将拟合结果与光谱仪测量波长数据进行比较.结果表明,高斯多项式拟合法精度和稳定性较好,且能满足实时性要求.     

啁啾效应对Bragg波长匹配解调精度的影响与消除

介绍了光纤光栅Bragg波长的匹配解调原理,分析了传感光纤光栅和匹配光纤光栅的反射谱相关函数, 说明相关函数与光电探测器输出信号具有线性关系。指出基于最大相关原理(光电探测器输出信号极值判断法)的匹配解调只适用于两个光纤光栅具有相同的反射谱型。采用光电探测器输出信号峰值判读时,传感光纤光栅的啁啾效应会引起Bragg波长的解调误差。理论分析和实验研究表明,对光 电探测器输出信号进行去卷积运算处理可以消除传感光纤光栅啁啾效应对Bragg波长解调精度的影响。     

基于桥梁结构的FBG传感器温度与应变交叉敏感问题的研究

对光纤布拉格光栅(FBG)传感器在桥梁结构健康监测中产生的温度与应变交叉敏感问题进行了研究。采用参考光纤光栅法在应变传感光纤光栅附近额外加入一个温度测量光纤光栅,对应变光栅实现温度补偿功能。设计了基于参考光纤光栅法的FBG传感器及FBG传感器封装的机械结构,并通过实验来验证FBG传感器的性能。实验数据表明,温度传感光纤光栅几乎不受应变的影响,应变传感光栅的中心波长变化与温度变化呈一阶线性关系,修正后的测量结果更加精确,达到了双参数同时测量的目的,应变与布拉格波长的线性关系非常好,相关系数达到0.99以上。参考光纤光栅法能够很好地解决FBG传感器温度与应变交叉敏感的问题。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.