Design and Investigation of a High-Sensitivity Tilt Sensor Based on FBG

In this paper,a high-sensitivity fiber Bragg grating(FBG)tilt sensor using a cantilever-based structure is introduced.Two FBGs are fixed on a specially designed elastomer.One end of the elastomer is connected to the mass block,and the other end is connected to the shell.The principle of the tilt sensor is introduced in detail,and the mathematical model is established.The performance of the sensor is studied.The results show that there is a good linear relationship between the central wavelength difference of the two FBGs and the tilt angle in the range of-5°to 5°.The repeatability of the sensor is good,and the tilt sensitivity can reach 231.7 pm/°.The influence of the silicone oil on the damping capacity of the sensor is studied.The results show that the damping capacity of the sensor has been improved by sealing the silicone oil inside the shell of the sensor.The field test is carried out on a pier of an elevated bridge,and the result is good,which verifies the practicability of the sensor.

Tilt Sensor Based on Intermodal Photonic Crystal Fiber Interferometer

A tilt sensor based on an intermodal photonic crystal fiber （PCF） interferometer is demonstrated. The sensor consists of a tubular filled with NaC1 aqueous solutions and an intermodal PCF interferometer, which is formed by using a short PCF with two single-mode fibers （SMFs） spliced at both ends, and the air-holes in the splice regions are fully collapsed. The intermodal PCF interferometer is fixed in a rigid glass tubular with a slant orientation, and a half of the PCF is immersed in the NaC1 aqueous solutions, while the other half is exposed in air. When tilting the tubular, the length of the PCF immersed changes so that the transmission spectrum moves. Therefore, by monitoring the wavelength shift, the tilt angle can be achieved. In the experiment, a 0.8-cm-length intermodal PCF interferometer was adopted. The sensitivity of the proposed sensor was obtained from - 1.5461 nm/° to -30.1244 nm/° when measuring from -35.1 ° to 37.05°.

On-Machine Measurement of the Straightness and Tilt Errors of a Linear Slideway Using a New Four-Sensor Method

Although there are some multi-sensor methods for measuring the straightness and tilt errors of a linear slideway, they need to be further improved in some aspects, such as suppressing measurement noise and reducing precondition.In this paper, a new four-sensor method with an improved measurement system is proposed to on-machine separate the straightness and tilt errors of a linear slideway from the sensor outputs, considering the influences of the reference surface profile and the zero-adjustment values. The improved system is achieved by adjusting a single sensor to di erent positions. Based on the system, a system of linear equations is built by fusing the sensor outputs to cancel out the e ects of the straightness and tilt errors. Three constraints are then derived and supplemented into the linear system to make the coe cient matrix full rank. To restrain the sensitivity of the solution of the linear system to the measurement noise in the sensor outputs, the Tikhonov regularization method is utilized. After the surface profile is obtained from the solution, the straightness and tilt errors are identified from the sensor outputs. To analyze the e ects of the measurement noise and the positioning errors of the sensor and the linear slideway, a series of computer simulations are carried out. An experiment is conducted for validation, showing good consistency. The new four-sensor method with the improved measurement system provides a new way to measure the straightness and tilt errors of a linear slideway, which can guarantee favorable propagations of the residuals induced by the noise and the positioning errors.

Optimization of the Tilted Fibre Bragg Gratings for the Fibre Accelerometric Sensor

The presentation shows the principle and construction of the fibre optic accelerometric sensor. The sensor element is based on the use of the tilted fibre Bragg grating (TFBG) that is imprinted to the bend insensitive single-mode telecommunication grade fibre. The fibre section with TFBG is then coupled to the evaluation fibre circuit with the cladding-core mode conversion element that provides the core re-coupling of the optical power injected by TFBG to the fibre cladding. The cladding-core mode conversion efficiency is sensitive to the acceleration generated fibre bending. It is shown that the sensitivity of the device depends on the rate of the main core reflection versus cladding ghost reflection induced by the grating. The analysis of the core reflection power coupling on the angle of the grating tilt and the analysis of the cladding ghost reflection power coupling on the angle of the grating tilt is presented and the optimal parameters of the tilt and refractive index modulation are derived. The presentation gives the experimental results of the TFBG sensor prepared according to the optimization process.

基于倾角反演的隧道断面变形全方位监测方法

倾角传感器具有体积小、使用方便、测量连续等优点,在隧道变形监测领域有着巨大应用潜力,然而,现有基于倾角传感器的监测方法往往只能得到特定监测点的变形,在测量隧道断面整体变形方面还存在明显不足。为此,提出一种新的基于监测点倾角的隧道断面变形全方位监测方法。基于隧道断面曲线的形状特征,构造隧道分段变形插值函数,根据极坐标下隧道倾角与极径的关系,采用分段解析方法提出隧道倾角-变形数学模型,进一步通过协同变形假定,修正隧道测点极角,得到隧道倾角-变形算法;接着,建立隧道三维数值模型,通过均布荷载、对称非均布荷载和非对称荷载3种典型工况,采用误差分析方法分别研究算法的适用性;最后,通过室内试验进一步验证算法在实际应用中的准确性。研究结果表明:对于铁路隧道典型三心圆断面,推导的倾角-变形算法在均布荷载、对称非均布荷载和非对称荷载这3种典型工况下均具有良好的适应性,变形最大绝对误差均小于1 mm,平均相对误差均小于7%;在室内模型试验中,拱顶沉降监测误差小于8%,水平收敛监测误差小于5%,证明了监测方法的准确性。

基于方差补偿AKF-BP的电解液式测斜仪精度提升研究

电解液式测斜仪广泛适用于测量土石坝、面板坝、岩土边坡、路堤、基坑等结构物的水平位移监测。为消除环境温度变化和测量噪声引起的电解液式测斜仪测量误差,进行了传感器温度实验,并对硬件本身、工作环境、数据采集三种测量误差影响因素和温度变化影响因素进行详细分析,提出了一种基于方差补偿自适应卡尔曼滤波(AKF)和BP神经网络(BPNN)的精度补偿模型;结果表明,补偿后的电解液式测斜仪水平位移的均方误差相较于补偿前平均降低了80%以上,从而有效减少计算水平位移的误差,极大提升了电解液式测斜仪的测量精度,可应用于电解液式测斜仪实际工程。

矿用FBG倾角传感器结构设计及传感性能分析

基于杠杆—摆锤结构与力学分析方法,利用差动补偿法消除温度对光纤布拉格光栅(FBG)波长漂移量的影响,建立波长与倾角传感的数学模型,分析矿用FBG倾角传感器传感特性。通过矿用FBG倾角传感器平台标定静态实验分析总结,铜基体表贴FGB传感器精度为1.526%、灵敏度为952.95 pm/(°)、重复性为1.2687%、迟滞性为0.2998%,结果表明:FBG倾角传感性能与实际倾角测量结果具有较好的一致性,为矿用FBG倾角传感器的应用提供理论技术支撑。

仿蜂鸟倾斜悬停的四旋翼系统设计

为了提高常规四旋翼的灵活性,模仿蜂鸟在空中倾斜身体悬停的特点,对一种改进后的轴可动四旋翼进行系统设计与验证。首先,在四旋翼的每个机臂上增加由舵机驱动的倾转装置,使得旋翼可以灵活地改变朝向,建立平台的六自由度模型;接着结合视觉传感器测量飞行平台的位姿,基于串级PID控制和线性的控制分配方法,基于嵌入式平台进行实物实验。结果表明,飞行器实现了静止在空中某一位置倾斜姿态,具有更高的灵活性。

基于IDBO-PID的联合收获机割台控制系统

该研究专注于提升无人农场联合收获机在复杂地形作业时,割台高度控制的精确性与响应速度。首先,提出了一种基于双倾角传感器的高度检测补偿方法,通过最小二乘法拟合建立割台倾角与高度的相关模型,相关系数0.9958,显著提高测量准确性。随后,引入群智能算法优化的PID控制策略,利用Bernoulli混沌映射、粒子群算法(PSO)、t分布扰动改进蜣螂优化算法,解决了传统PID控制的精度低和响应慢等问题。基于这些优化,IDBO-PID控制器在仿真对比中相较于DBO-PID和传统PID,具有更优的响应速度和稳定性。试验验证表明,改进的控制策略使割台的上升速度达到0.44m/s、下降速度达到0.32m/s,并且高度误差控制在0.02m内,满足作业需求。

三杯风速传感器非水平风场测量性能

为解决三杯风速传感器在计量检定条件下与观测场景中环境差异所导致的测量数据误差,致力于研究空气流速计量标准在量值传递过程中的真实性、准确性和一致性,为新一代三杯风速传感器作为计量器具的新产品型式评价提供思路和参考指标,依据杯式测风仪测量方法与自动气象站风速风向传感器检定规程,并在实验中加入了主体由角度编码器构成的自动化转盘系统,设计了三杯风速传感器在非水平风场内测量性能水平实验。通过调整三杯风速传感器在风洞试验段内的倾斜角度,模拟其在自然界非水平风场中的测量状态,同步采集风洞的标准指示风速、三杯风速传感器的实测风速以及其相应的倾斜角度,计算示值误差,利用方差分析、趋势分析、相关性分析和线性回归分析等统计方法,对不同倾斜角度下三杯风速传感器示值误差进行研究,得出了三杯风速传感器在风洞试验段内的示值误差与实测风速和倾斜角度之间的相关关系,提出了三杯风速传感器在非水平风场下的测量性能指标。研究了三杯风速传感器在非水平风场中实测风速与标准风速和倾斜角度的回归关系,提出了三杯风速传感器在计量环境下非水平风场中数据的量值传递修正算法。

计及边缘效应的差动圆柱面电容式倾角传感器的输出特性

为了研究差动圆柱面电容式倾角传感器在计及边缘效应情况下的输出特性,将保角变换法、格林函数法和计算机数值模拟相结合,讨论差动圆柱面电容器中的电场,给出其电容量随倾角变化的函数式,绘制出该传感器输出特性曲线,分析影响该传感器线性度及灵敏度的因素,并指出改善该传感器输出特性的途径。

计及横向边缘效应的摆式差动电容倾角传感器输出特性

为了研究计及极板横向边缘效应的摆式差动电容倾角传感器的输出特性,利用保角变换法和格林函数法,讨论电容式倾角传感器的电场,得到其电容量随角位移的变化关系,通过MATLAB软件绘制出该传感器输出特性曲线,并对影响该传感器输出特性的因素做了定量分析。仿真模拟结果显示,在传感器的动极板的宽度小于静极板时,增大两极板的宽度差,再适度增大极板的间距,并减小极板直缝隙的宽度,可提高该传感器灵敏度及线性度,改善其输出特性。

起重设备防倾覆智能化装置

为了解决起重设备在使用过程中可能出现的机械和人为原因引起的倾覆问题,将智能化技术引入到起重设备的设计、操作和后期的维护保养中,有效预防这些风险因素的产生。这些技术包括智能化吊具、防摇摆与精确定位、路径规划与障碍物避让、无线传输、视频监控等。通过这些技术,智能化装置不仅可以代替人的操作实现起重机自动运行,还可以实时监控起重机的工作状态,预测并避免可能的风险,从而确保起重机的安全和稳定运行,降低企业的运营成本。

基于倾角检测仪的水平井定向桥射联作技术

在定向桥射联作施工中,当射孔枪泵送至井下水平段射孔位置后,利用现有技术手段无法检测射孔弹发射口的朝向。通过研制倾角检测仪和全集成定向射孔装置,将选发控制芯片和三轴加速度传感器集成于一体,设计控制电路实现分簇射孔的起爆控制,实时测量射孔弹的方向并上传至地面选发控制系统;当检测到射孔弹方向不正确时,拖动枪串重新泵送使弹架旋转并重新定向,如果射孔弹方向仍不正确,则起出工具串整改后再施工。该技术使得接头与弹架触点连接无需接线,缩短了施工时间,方向测量角度偏差≤2.00°。在F196-XP34井现场应用11段,成功率100%。该技术可应用于所有水平井定向桥射联作,尤其适用于套管外避光纤的射孔工艺,具有较大的推广应用价值。

准确检测液相中氢气浓度的倾斜光纤光栅传感器

为了实现液相中氢气体积分数的准确检测,该文利用钯、氧化硅超疏水溶胶和倾斜光纤光栅制备了氢气传感器。首先,在倾斜光纤光栅表面采用磁控溅射法涂覆了一层致密的钯膜,用于响应氢气体积分数变化信息;然后,采用镀膜提拉法在钯膜表面涂覆一层氧化硅超疏水膜,用于阻止水分子进入钯膜内部,导致钯膜从光纤表面脱落,进而增强了传感器在液相环境下运行的稳定性。实验研究了钯膜厚度对传感器氢敏响应特性的影响,并利用传感器对液相中的氢气体积分数进行了检测。研究结果表明,传感器能准确响应液相中氢气体积分数的变化信息,当钯膜厚度为120 nm时,灵敏度达到-15.29 pm/%,最大相对误差为8.67%。

Pure Bending Characteristic of Tilted Fiber Bragg Grating

a novel structure of the pure macro- bending sensor based on the tilted fiber Bragg grating （TFBG） is proposed. The TFBG located in the half circle with the different diameters is bent at a constant angle with respect to the tilted grating planes. With the variations of the curvature, the core-mode resonance is unchanged and the transmission power of cladding modes detected by the photodiodes varies linearly with curvature, while the ghost mode changes by the form of two-order polynomial. So we can use the transmission power of ghost mode or other cladding modes to detect bending curvature as shape sensor. From a practical point of view, the sensor proposed here is simple, low cost and easy to implement. Moreover, it is possible to make a temperature-insensitive shape sensor due to the same temperature characteristic between the core mode and the cladding modes.

输电铁塔倾斜远程监测系统

为减少因输电铁塔倾斜而引发的电力故障,将输电铁塔倾斜监测由被动防御转为主动预防,文中设计了基于MEMS传感器输电铁塔倾斜监测系统。系统采用改进的CKF算法对MEMS传感器信号进行滤波,通过引入自适应比例因子λk调节CKF滤波增益,增强对MEMS传感器信号的适应性,提高滤波精度。然后通过欧拉角与四元数变换进行姿态解算,处理后的数据通过ZigBee与GPRS技术传送到远程监测终端,实现输电铁塔倾斜在线监测。实验室测试表明,改进的CKF算法能够将倾斜角测量误差控制在0.07°以内;现场实验表明,系统能够及时采取报警动作,克服传统监测模式的不准确性、滞后性,具备较强的续航能力。

双层反倾线圈结构的直线时栅位移传感器研究

针对前期研究的双层直线时栅位移传感器测量误差成分中四次谐波较大,影响传感器测量精度的问题。根据双层激励线圈的结构特点,提出了一种双层反向倾斜线圈结构的直线时栅位移传感器设计方案。通过构建双层反倾线圈产生磁场的数学模型,分析了双层反向倾斜线圈的磁场状态,并利用电磁场有限元仿真分析双层反倾线圈直线时栅位移传感器中倾斜大小和动定尺之间的气隙对测量误差与误差谐波成分的影响,确定了最优化的设计参数。采用PCB(Printed Circuit Board)工艺研制了78个节距大小的传感器样机并进行了精度测试。实验结果表明,双层反倾斜线圈结构对原双层直线传感器中误差四次谐波抑制效果显著,在同样设置条件下,将原测量误差成分中四次谐波从40μm抑制到7μm,抑制效果达到82.5%。最终经过误差修正后的传感器对极内精度达到±13μm。

大型船闸反弧门运行状态检测方案

目前船闸反弧门启闭位置控制主要依赖于开度检测装置和位移传感器,由于船闸反弧门在高水头下动水启闭频繁,当吊杆连接轴及轴套磨损后,会造成反弧门启闭位置误差逐渐增大,使得反弧门存在超关现象,进而对反弧门门体、止水、底坎埋件造成破坏。针对此问题,从提高启闭控制系统的精度方面对船闸反弧门运行状态检测方案进行研究。分析了反弧门位置控制系统存在的问题,采用在反弧门门体内部安装倾角传感器的方式对启闭位置角度信息进行检测,提高了启闭位置控制精度。2021年在葛洲坝三号船闸右充反弧门实施了运行状态检测装置的安装施工与测试,验证了反弧门运行状态在线检测系统的技术可行性以及检测水平的先进性。

基于非本征法珀干涉的自动温度补偿倾角传感器

提出并证明了一种基于非本征法布里—珀罗干涉(EFPI)原理具有自动温度补偿功能的高精度光纤倾角传感器。传感器采用EFPI原理和柔性绳悬挂质量块的结构,无需弹性元器件,通过直接测量质量块的位移来测量倾角。利用2只EFPI传感器的腔长差消除温度影响,实现了高达±0.15″(角秒)的角度分辨率和0.01″/℃的超低温度灵敏度。通过对水电站倾角的监测,验证了该传感器在水利工程等建筑物的长期倾角监测中的适用性。