多芯光纤光栅形状传感性能与重构误差研究

多芯光纤光栅形状传感技术利用空分复用以及应变监测的优势,结合不同的栅点布设方案,实现待测对象的连续曲率和形状传感。首先介绍了多芯光纤光栅曲率和挠率传感原理,提出采用齐次矩阵变换的三维重构算法实现光纤的三维形状重构。为了探究不同光栅密度对实验精度的影响,利用算法编程模拟了不同光栅间距下的三维形状重构精度,依据模拟仿真的结果,建立了不同光栅间距与三维重构误差之间的关系。三维形状传感实验使用光栅间距为10 cm和5 cm的七芯光纤光栅串。实验结果表明,最大误差出现在尾点处,分别为2.56 cm和1.15 cm,占全长的3.2%和1.4%,平均误差为1.32 cm和0.62 cm,占全长的1.7%和0.8%。实验结果与仿真值比较接近,说明可以依据仿真结果对不同光栅间距下的三维形状误差进行预测。结合具体的应用场景合理配置测点资源,在较低的成本范围内实现高性能的检测。     

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%。     

基于互补型格雷编码的离焦二元光栅相位展开方法

离焦投影使编码光图像黑白灰级跳变产生模糊而 造成二值化错误,导致相位级次解码 出错,影响相位展开。本文提出利用互补型格雷编码光计算相位级次,完成离焦二元光栅相 位展开。生成两种编码光序列,出现误码的位置相互交错,具有互补性。结合 两种互补性编码光图像进行相位展开,可有效避免编码光图像二值化错误所引起的误码影响 。对陡 变物体测量的结果表明,相位相对误差(RE)为1． 03％,误差峰谷值(PV)为0.24rad,均方差(RMS )为0.14rad。本文方法提高了离焦二元光栅测量精度 ,扩大了测量范围,尤其适用于陡变或不连续物体的三维面形测量。     

激光-CCD微位移传感器测振研究

本文介绍了利用激光-CCD微位移传感器测振的原理和方法。这种测量技术适用于检测较大的振幅值(>60/Am)。在60～800/bm范围内,最大绝对误差<10灿m,相对误差<6％。     

双模态信息融合的飞行目标位姿估计方法

针对在飞行目标位姿估计中背景复杂、目标提取及位姿解算精度低、速度实时性差等问题,提出了一种激光与图像信息融合的飞行目标位姿估计方法。首先,建立彩色相机和激光雷达间的坐标变换模型实现两传感器像素级匹配,对同一时刻的图像和点云进行融合处理;其次,采用Vi Be算法与深度信息融合对图像中运动目标进行提取,并根据图像目标的位置框选出对应的点云;最后,利用PnP算法进行特征点粗配准,获取点云间初始旋转平移矩阵,并采用迭代最近点算法进行精配准,利用IK-D Tree加速临近点搜索,提高配准速度。使用仿真试验和半实物仿真试验对方法准确性和稳定性进行了验证,结果显示：二维图像目标检测算法正确率为97%,错误分类比为0.011 2%;位姿估计算法与传统迭代最近点算法相比精度提高了53.2%,单次耗时从261 ms降低至132 ms,效率提升约49.4%,与其他算法相比也具有一定优势。为飞行目标落点精准预测和制导控制提供解决思路。     

SQUID arrays for simultaneous magnetic measurements: calibrationand source localization performance

Recently developed small arrays of SQUID- (superconducting quantum interference device) based magnetic sensors can, if appropriately placed, locate the position of a confined biomagnetic source without moving the array. A technique is presented having a relative accuracy of about 2% for calibrating such sensors having detection coils with the geometry of a second-order gradiometer. The effects of calibration error and magnetic noise on the accuracy of locating an equivalent current dipole source in the human brain are investigated for five- and seven-sensor probes and for a pair of seven-sensor probes. With a noise level of 5% of peak signal, uncertainties of about 20% in source strength and depth for a five-sensor probe are reduced to 8% for a pair of seven-sensor probes, and uncertainties of about 15 mm in lateral position are reduced to 1 mm for the configuration considered     

基于多体制探测数据融合的MUF预报方法

提出了一种基于多体制探测数据融合的最高可用频率（maximum usable frequency，MUF）预报方法.该方法基于数据融合的思想，将电离层垂测数据和斜向探测数据进行融合处理，对短波通信最大可用频率进行预报，试验结果表明，该方法能够有效提升对MUF预报的准确性，预报相对误差降低19.23%，绝对误差降低0.33 MHz；对比实验结果，春秋季和冬季的预报精度提升尤为明显，平均达到25%以上，夏季能达到10%以上.该方法易于工程实现，能够对短波通信选频、短波广播覆盖分析等提供准确的数据支撑.     

Sensing clouds: A distributed cooperative target tracking with tiny binary noisy sensors

This paper suggests a novel algorithm for mobile object tracking using wireless sensor networks (WSNs). The paper assumes a future model of WSNs, where a large number of low to medium range inexpensive and noisy sensors are distributed randomly over an area. The distributed algorithm is based on short range communication between neighboring sensors, and is designed to work with very basic low cost binary sensors, that can report only a sensing, not sensing value.Neighboring sensors that sense the object form a cloud around the object which is dynamically updated as the object moves. To save energy on reporting a subset of the cloud, the cloud core, is elected. A trade-off between the accuracy and the core size (namely transmission power) is presented, as well as an extensive simulation study. Our algorithm works well with false negative sensing and up to 10% false positive sensing.     

使用双传感器系统降低光刀图像缺损误差

用线结构光扫描测量三维物体的过程中,由于物体表面的凹凸不平、反射率的不连续变化以及遮挡造成获取的条纹像存在各种缺陷,导致最后得到的三维面形数据存在偏差。基于此,提出了一种采用双传感器,并将两个传感器图像映射到光刀平面上,然后再对其进行面内融合处理最后提取中心线的方法。对此方法进行了计算机模拟,并对牙齿进行了测量。实验结果表明该方法实现简单,在存在条纹缺陷的地方,精度可以明显提高,有效地降低了条纹缺陷导致的数据偏差。     

通道式偏振遥感器偏振解析方向测量误差分析及验证

通道式遥感器的偏振测量核心部件通常是相似的,即不同偏振解析方向的检偏器组合进行探测。同一系统中不同偏振解析方向之间的相对角度误差成为影响偏振遥感探测精度的重要因素之一。文中对该相对角度误差的影响以及提高测量精度的方法进行了研究。首先,分析了相对角度误差对偏振测量精度的影响;其次,对测量过程中存在的误差源进行了仿真分析及实验对比分析,根据该设计具体的实验参数和实验方法,验证仿真结果的正确性;最后,通过通道式遥感器偏振实测结果验证其测量的可靠性。系统偏振度测量值与可调偏振度光源输出的偏振度参考值比对,最大平均偏差为0.735 3%;与CE318测量比对的最大平均偏差为0.036。实验结果满足实际使用的偏振测量精度要求,说明偏振解析方向测量方法选择合理,可以为偏振遥感器的装调和高精度定标提供参考。     

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。     

Three-dimensional touch interface for medical education.

We present the technical principle and evaluation of a multimodal virtual reality (VR) system for medical education, called a touch simulator. This touch simulator comes with an innovative three-dimensional (3-D) touch sensitive input device. The device comprises a six-axis force-torque sensor connected to a tangible object representing the shape of an anatomical structure. Information related to the point of contact is recorded by the sensor, processed, and audiovisually displayed. The touch simulator provides a high level of user-friendliness and fidelity compared to other purely graphically oriented simulation environments. In this paper, the touch simulator has been realized as an interactive neuroanatomical training simulator. The user can visualize and manipulate graphical information of the brain surface or different cross-sectional slices by a finger-touch on a brain-like shaped tangible object. We evaluated the system by theoretical derivations, experiments, and subjective questionnaires. In the theoretical analysis, we could show that the contact point estimation error mainly depends on the accuracy and the noise of the sensor, the amount and direction of the applied force, and the geometry of the tangible object. The theoretical results could be validated by experiments: applying a normal force of 10 N on a 120 mm x 120 mm x 120 mm cube causes a maximum error of 2.5 +/- 0.7 mm. This error becomes smaller when increasing the contact force. Based on the survey results, the touch simulator may be a useful tool for assisting medical schools in the visualization of brain image data and the study of neuroanatomy.     

一种基于位置敏感器相位检测的振动测量方法

针对微机械系统和精细加工技术中现有的振动测量方法存在易受电磁干扰、动态和线性范围窄等诸多问题,本文提出了一种基于一维位置敏感器(PSD)相位检测的振动测量方法,通过激光三角法将被测物体的振动信号转换为光斑在PSD的位置变化,PSD两电极输出的电流相差信号经PSD相位法的信号处理电路转换为与光斑位置成线性关系的直流电压信号,由此确定光斑的位置变化,进而测量物体的振动,且实时信号可以通过示波器或在上位机界面中显示。本文实验测量的平均相对误差为0.89%,最大误差为1.75%,线性度优于1.2%,实现了振动的高精度、高线性度和不受电磁干扰的测量。     

面向室内动态场景的VSLAM

传统VSLAM算法基于静态场景实现,其在室内动态场景下定位精度退化,三维稀疏点云地图也会出现动态特征点误匹配等问题.文中在ORB-SLAM2框架上进行改进,结合Mask R-CNN进行图像的语义分割,剔除位于动态物体上的动态特征点,优化了相机位姿,得到了静态的三维稀疏点云地图.在公开的TUM数据集上的实验结果表明,结合...     

超连续激光单色仪系统级光谱响应度定标比对验证

细分光谱扫描定标技术是实现遥感器高精度光谱辐射定标的重要方式,基于超连续激光单色仪的定标装置是实现遥感器细分扫描定标的新选择。为验证所建立的超连续激光单色仪装置的系统级定标能力,利用硅辐亮度计和滤光片辐射计,分别采用超连续激光单色仪定标装置和可调谐激光定标装置对其进行了系统级绝对光谱响应度定标比对验证。实验结果表明:在所验证波段范围内,两种定标装置获得的硅辐亮度计绝对光谱响应度系统级定标结果最大偏差为0.6%。通道式滤光片辐射计的带内绝对光谱响应度定标结果最大偏差优于0.4%,带内积分响应度最大偏差约0.1%。文中的研究验证了超连续激光单色仪定标装置具有良好的系统级定标能力,能够获得较高的定标精度,在遥感器的绝对光谱响应度定标中具有重要应用前景。     

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%。     

Array FBG sensing and 3D reconstruction of spacecraft configuration

In this paper, a plate shape perception technique based on quasi-distributed fiber Bragg grating (FBG) array and space surface reconstruction algorithm is proposed. Firstly, in order to make curvature continuous, the bicubic plane interpolation algorithm is studied. Then, taking the simulated satellite bulkhead structure as the research object, we research the space surface reconstruction algorithm based on orthogonal curvature and coordinate transformation (translation and rotation). Finally, a four-sided fixed plate deformation monitoring system based on quasi-distributed FBG sensors network and surface reconstruction algorithm is built. Many experiments are conducted to verify the reliability and accuracy of the algorithm. The proposed algorithm provides a new method for three-dimensional reconstruction of spacecraft structure.     

基于位姿评估的无线传感器网络自主移动节点定位技术

 本文在研究自主移动节点运动特性的基础上,提出一种基于位姿评估技术的自主移动节点定位算法.该算法适用于可以获取速度信息以及具有射频定位功能的移动节点.该算法利用移动节点速度信息计算相对定位轨迹;然后对相对定位轨迹进行平移,旋转变换,使变换后的相对定位轨迹与射频定位轨迹的结果差别最小来修正累积误差;最后从修正后相对定位轨迹上获取最终定位结果.仿真实验结果表明,所提出的算法在参数取值合理的条件下,能够有效地提高移动节点定位精度.     

A rotating inertial navigation system with the rotating axis error compensation consisting of fiber optic gyros

An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system (RINS). The accuracy of single-axial RINS is limited by the errors on the rotating axis. A novel inertial measurement unit (IMU) scheme with error compensation for the rotating axis of fiber optic gyros (FOG) RINS is presented. In the scheme, two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error. Without any change for the rotation cycle, this scheme improves the system’s precision and reliability, and also offers the redundancy for the system. The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS, besides the heading accuracy is increased by 3 times compared with single-axial RINS, and the position accuracy is improved by 1 order of magnitude.     

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。