免受温度影响的光纤光栅线性扭转传感器

设计了一种新颖的组合式扭梁传感结构 ,利用外直径相等的实心梁与空心梁界线两侧应变分布的差异 ,将一定长度的光纤光栅沿与轴向呈一定角度刚性粘贴于界线的表面 ,通过测量界线两侧光纤光栅反射波长的差值 ,首次实现了免受温度影响的光纤光栅扭转传感测量。理论分析和实验结果证明 ,该传感装置能够自动消除扭转传感与温度的交叉敏感效应 ,界线两侧光纤光栅反射 (或透射 )波长漂移的差值对扭角、扭矩及扭力 (力臂一定时 )均呈线性关系 ,与温度变化无关。在± 4 0°扭角范围内 ,扭角、扭矩的传感灵敏度分别达到 0 0 92nm degree ,2 0 76nm Nm。     

Linear fibre-grating-type sensing tuned by applying torsion stress

The characteristics of fibre-grating-type sensing tuned by applying torsion stress are studied for both the solid column beam and air-core column beam. The wavelength shift is linear with respect to the torsional angle and torque in the range between -45 and +45°. The tuning ranges are no less than 7 nm     

利用单光纤光栅实现力学量垂直感测的研究

通过改进悬臂梁自由端结构设计 ,利用光纤光栅波长绝对编码的特性 ,实现了利用单光纤光栅对应力、位移进行了垂直感测。理论分析和实验结果证明 ,通过监测粘贴于悬臂梁固定端附近的光纤光栅波长变化的大小和指向 ,能够感测应力、位移等力学量的大小及方向。在相互垂直的方向上 ,获得的应力实验灵敏度分别为 1 87nm N和 3 4 0nm N ,位移实验灵敏度分别为 0 2 3nm mm和 0 4 1nm mm。     

Simultaneous sensing of displacement and temperature with a single FBG

A novel fiber Bragg grating (FBG) sensor with simultaneous sensing of displacement and temperature is presented. The FBG is affixed on the cantilever inclinedly. The midpoint of FBG exactly coincides with the zero strain layer of a rectangular beam. The vertical displacement can be measured by the broadened bandwidth of FBG as the bandwidth is insensitive to temperature, while the temperature can be measured by the center wavelength shift as the wavelength shift is insensitive to vertical displacement. With 0.1 nm spectral resolution of the analyzer, sensitivities of bandwidth-displacement and center wavelength-temperature are 0.48 nm/mm and 0.05 nm/°C, resolutions are 0.2 mm and 2.0 °C, and sensing ranges of displacement and temperature are up to 8.5 mm and 45°C respectively. Experimental results match theoretical analyses very well.     

基于弹性梁的光纤光栅波长调谐原理及技术

光纤光栅波长调谐在光纤通信和光纤传感器领域中具有重要意义和实用价值。从理论上分析了基于弹性梁的光纤光栅波长调谐的基本原理,阐述了几种典型的简支梁、悬臂梁及扭梁调谐技术及其特点,展望了波长调谐方法的未来发展。     

一种应力迟滞和温度自动补偿型FBG压力传感器

基于波登管与悬臂梁的组合设计,将2个相同波长的光纤布拉格光栅(FBG)分别与悬臂梁的上、下表面对称粘贴组成差动式FBG传感系统,实现了外压力调谐双FBG布拉格波长差的调谐方法。理论分析和实验研究结果表明,该系统不仅能自动补偿FBG压力传感系统中弹性衬底元件在加压和减压过程中的弹性迟滞,而且能同时自动补偿温度,改善传感系统的线性响应特性;在0～20MPa的压力范围内,双峰波长差的调谐范围为0.0～5.6nm,压力调谐双峰波长差的灵敏度可达0.28nm/MPa,是压力调谐单峰波长灵敏度的2倍,标准误差可由单峰的0.066nm降低到0.0084nm。     

一种双梁互补式光纤光栅位移传感器及在地铁隧道变形监测中的应用

本文提出了一种双梁互补式光纤光栅(fiber Bragg grating, FBG)位移传感器,实现了正负双向位移的测量。采用双“悬臂梁+楔形滑块”的结构,当一个悬臂梁受位移作用处于变形状态时,另一个悬臂梁不变形并提供温度补偿功能。传感器处于零值测点状态时,两个悬臂梁处于零弯曲状态,且双梁互为温度补偿,消除了温度影响。通过性能测试实验证明,该传感器在±50的量程内,灵敏度为29.369 pm/mm,测量重复性好。制备出8个传感器应用于某市地铁的变形安全监测,从道床沉降、道床环缝、管片环缝3个方面开展了变形测量。在长期监测期间,传感器工作稳定,被测结构变形状态稳定,表明该传感器具有良好的测量性能,适用于长期的结构健康监测。     

FBG弯曲传感在滑坡预警监测中的应用研究

针对传统滑坡预警监测技术中存在的自动化程度 较低、测量精度不高,不易对边坡实现大面积和长 期可靠在线监测等不足,研究了采用光纤光栅(FBG)弯曲传感技术用于边坡表面形变及深 部位移测量的 结构原理及具体应用方式。在分析采用简支梁和悬臂梁两种结构实现FBG弯曲调谐原理 的基础上,选择具有不同中心波长的FBG进行串接后,粘贴于弹性杆件PVC管上,实验验 证了利用简支梁和悬臂 梁两种FBG弯曲调谐结构实现边坡表面形变及深部位移进行原理性测量的可行性。实验结果 表明,粘贴在 PVC管上不同位置的FBG的波长变化量与该位置的形变量有着明显的线性对应关系;两种结构 最大形变位 置的FBG测量灵敏度分别为0.245 nm/mm和0.166nm/mm;采用在PVC管两侧对称180°的位置粘贴 FBG的方法,可在提高FBG检测灵敏度的同时,解决FBG温度及应变的交叉敏感问题,消除环 境温度变化对FBG弯曲传感测量结果的 影响。     

Fabrication of low-stress low-stiffness leveraged cantilever beam for bistable mechanism

This paper presents the fabrication and application of a leveraged cantilever beam with low-stress and low-stiffness. This cantilever beam is overhanged with two free ends and suspended in air by the supporting torsion flexures fixed at its middle. The teeterboard-typed cantilever features a low-stiffness with 1.63 N/m, and a low-stress with ±6.27 MPa. The cantilever beam was prepared by a laminated photoresist sacrificial layer process (LPSLP), that is, a multilayered photoresist film for supporting the suspended cantilever beams. In this work, two main problems related to microfabrication process were discussed. One is the control of residual stress in permalloy cantilever with varying the contents of additive saccharin to minimize the deformation of the free end of the beams. The other is an improved wet release method to avoid the adhesion or stiction of the all metal microstructures. The proposed leveraged cantilever beam has a potential application on the bistable switching mechanism in single-pole-double-through (SPDT) latching relay fields. Switching between two stable states of the microbeam mechanism was successfully validated with WYKO NT1100 optical profiling system.     

基于靶式和悬臂梁的FBG流量/温度同时测量研究

提出一种基于靶式结构和悬臂梁结合的新型流量/温度同时测量的光纤Bragg光栅(FBG)传感器。当流体流过传感器,流速的变化引起圆形靶产生应变,应变传递到等强度悬臂梁1上,进而引起粘贴其上的FBG1波长发生改变,而粘贴在悬臂梁2上的FBG2波长不发生改变;流体温度发生变化会引起FBG1、FBG2波长同时发生改变,且波长改变相同;通过测量两光栅的波长,得到流体的流量和温度。在水和蓖麻油实验得到:传感器的流量测量范围分别是400～2200cm3/s和700～1800cm3/s,温度测量范围是0～100℃。     

Design and fabrication of silicon-based 8×8 MEMS optical switch array

Silicon-based torsion-beam 8×8 optical switch array are designed and fabricated with bulk silicon micromachining technology. Torsion beams and cantilever beams with reflective micromirror situated on the same wafer are fabricated on (1 1 0) silicon. During fabricating the torsion beam actuating structure, the etched hillocks on (1 1 0) plane are obstacles to achieve smooth torsion beam. It is put forward the reasonable ratios mixtures of HF, HNO₃ and CH₃COOH to improve the processes of fabricating torsion beam actuating structure. The slanted under electrodes that can reduce the actuating voltage are designed and fabricated on tilting (1 1 1) plane by wet chemical etching. According to the etching characteristics of (1 1 1) silicon in KOH solution, two designed photomask patterns are proposed in this paper. According to the experimental results, for the 180 μm displacement of mirrors, the device presents the switching time less than 6 ms and the actuating voltage about 65 V. It shows that this optical switch array can make the meet of the optical communication network.     

纯弯梁无啁啾光纤光栅调谐方法

利用简支梁和悬臂梁调谐光纤光栅布喇格波长将造成光纤光栅啁啾。提出了一种新型的纯弯梁调谐方法 ,并进行了理论和实验研究 ,实现了光纤光栅无啁啾调谐 ,用于光纤光栅外腔半导体激光器获得了± 1nm的激光波长稳定连续调谐     

单个光纤光栅实现对位移和温度的同时测量

结合光纤光栅悬臂梁调谐的特点 ,采用一种新颖的光纤光栅悬臂梁结构 ,将光纤光栅粘贴在悬臂梁和固定端基板的结合处 ,成功地实现了对位移和温度的同时测量。基于光谱分析仪 0 1nm的光谱分辨率 ,实验可得到的位移分辨率为 0 0 8mm ,温度分辨率为 3 1℃ (位移不变时可达 0 73℃ ) ,位移测量范围可达 10 5mm。实验结果与理论分析基本一致     

Design and implementation of a bistable microcantilever actuator for magnetostatic latching relay

This paper presents the design, fabrication, and implementation of a microcantilever actuator with magnetostatic latching for performing low power bistable relay applications. This unique bistable feature consists of a low-stiffness torsion/cantilever beam system with circular-shaped support and a permanent magnet for holding the closed state with a permalloy soft magnetic circuit. The special circular support is designed to enhance the stiffness of the overhang beams. First, mechanical modeling of the leveraged torsion/cantilever beams was performed by Castigliano’s theorem so as to deduce the spring stiffness of system. Then the device has been prepared by a laminated photoresist sacrificial layer process (LPSLP). Finally, mechanical performance was characterized by atomic force microscopy (AFM), combined with finite element simulation using ANSYS™ package and analysis model as well. Switching between two stable states of the microactuator was successfully validated with WYKO NT1100 optical profiling system.     

光纤Bragg光栅温度与应力的测量分析

采用了一种基于等度强悬臂梁的双光纤栅组合法,实现温度与应力的同时测量。选用同一批次生产的参数一致的两根光纤Bragg光栅,将其分别粘贴在等强度梁的上下表面,通过梁上下光栅所受的应力大小相等而方向相反,产生两个反射峰来实现温度与应力的同时测量。通过实验测得光栅温度灵敏度系数为0.1346nm/℃,梁上下光栅误差仅为0.0001nm/℃;应力灵敏度系数分别为0.4085nm/N,-0.4089nm/N,误差也仅为0.0004nm/N。实验结果表明该方法切实可行,制作工艺简单,克服了传统双光栅组合法难以保证测量位置的准确性的缺点。     

一种“回”字形多方向压电能量收集方法

该文介绍了一种“回”字形的多方向微型压电振动能量收集装置,其由尺寸为34 mm×2 mm×1 mm的正方形边框包围,内部结构包含4个非对称的组合悬臂梁,主悬臂梁固定于边框内壁,并与z 方向垂直,次悬臂梁连接在主悬臂梁的末端质量块上。首先建立基础激励条件下组合悬臂梁振动系统的动力学模型。然后,通过有限元仿真分析对比了不同刚度和质量对位移幅值的影响,验证了组合悬臂梁系统的振动特性,并确定了最佳结构参数值:当主、次悬臂梁厚度均为0.3 mm,主、次质量块的最佳惯性质量分别为619.32 g、342.3 g。经仿真计算得到z 方向可输出电能功率为3.138 5 mW,x、y 方向可输出功率均为0.720 5 mW。最后搭建微型能量收集器实验平台,在实际测试中z 方向的输出功率为2.85 mW,x、y 方向的输出功率均为0.57 mW。     

FBG-type sensor for simultaneous measurement of force (ordisplacement) and temperature based on bilateral cantilever beam

An improved FBG-type sensor for simultaneous measurement of force (or displacement) and temperature based on the bilateral cantilever beam (BCB) is proposed and demonstrated. The two parts of the beam are subject to opposite forces (or displacements) leading to a red shift for the part of the FBG subject to stretch and to a blue shift for the other one. An FBG bonded to the surface of the middle of the BCB is experimentally demonstrated to have a force sensitivity of ~1.046 nm/N, a sensitivity of the displacement-based strain of ~0.317 nm/mm, and a temperature sensitivity of ~0.190 nm/°C between 0°C and 70°C, respectively     

应力测量的光纤光栅调谐技术的研究

光纤光栅波长调谐在光纤传感领域中具有重要意义和实用价值。从理论上分析了基于悬臂梁的光纤光栅波长调谐的基本原理,阐述了等强度悬臂梁调谐技术及其特点。基于光谱分析仪0.1nm的光谱分辨率的测量,实验结果与理论分析一致。实验装置构形简单、成本低,有较好的线性,易于定标和操作。     

Micromechanical accelerometer integrated with MOS detection circuitry

A cantilever beam accelerometer is described in which the small cantilever sensing element is integrated with and fabricated alongside MOS detection circuitry. The total area of the detector/circuit combination is about 15000 µm²(24 mil²). Fully compatible and conventional materials and processing steps are employed throughout the fabrication schedule. Accelerations of the chip normal to its surface induce motions in the cantilever beam. These motions result in capacitance variations which drive the simple MOS detection circuit. Sensitivities of about 2.2 mV/g of acceleration were measured, corresponding to beam motions of about 68 nm/g, with a beam mechanical resonant frequency of 2.2 kHz. These results were in close agreement with detailed mechanical calculations and circuit modeling.     

可调谐微腔发光二极管微光机电系统悬臂梁的特性

采用微机械表面加工技术,成功设计并研制出具有GaAs基微光机电系统(MOEMS)悬臂梁结构的可调谐微腔发光二极管。对其工作特性进行了分析,测量得到悬臂梁载荷-位移关系曲线,并对微光机电系统悬臂梁可调谐微腔发光二极管进行调谐光谱测量。实验结果表明,在直流电流40mA,调谐电压范围4～22V时,波长从974.5nm蓝移至956.9nm,室温下波长调谐最大达到17.6nm。在实验基础上,采用有限元方法对具有分布布拉格反射镜(DBR)结构的悬臂梁动力学特性进行了研究,模拟结果与实验结果吻合较好。当悬臂梁长度为400μm时,最大位移达到411nm,最大调谐电压达到24V。