基于硬件卡尔曼滤波的飞秒激光实时绝对测距精度优化方法

飞秒激光飞行时间测距是一种新型的绝对测距手段,具有精度高、量程大、可以同时测量多个目标等优点。其测量误差主要来源于飞秒激光源的量子噪声,为了保证高测量精度,可以采用多次测量取平均,然而这会使测量更新速率受限。文中采用FPGA作为距离解算的高速信号处理单元,利用Verilog语言设计了卡尔曼滤波硬件算法,对1.5 m处的合作靶标开展了测距实验,在1.5 kHz的更新速率下,测距标准偏差达到1.47μm,目标以20μm为步长运动时,测距仪能够准确更新目标位置。卡尔曼滤波硬件算法的引入不仅实现了高精度、高更新速率的绝对测距,并有效地提升了飞秒激光绝对测距装置的便携性。     

激光扫描追踪人体目标位姿的算法研究

针对人体目标位姿的追踪问题,对二维激光扫描仪的工作原理进行了归纳,对所测取数据的分析算法进行了研究,设计了一种基于激光图像扫描的新型算法,利用C语言与Matlab混合编程,通过对人体目标肩部截面进行椭圆拟合,实时测取了运动人体目标的距离、角度和方位信息,并通过Matlab GUI显示.二维激光扫描仪通过旋转的光学部件发射光脉冲,形成了二维的扫描面,以实现区域扫描及轮廓测量的功能.研究结果表明,利用激光扫描仪测取的人体目标的位置信息与真实的人体目标的位置信息相比基本吻合,距离范围为0m～4m,距离精度优于0.05 m,角度范围为240°,角度跟踪精度优于2°,方位范围为360°,方位精度最高1 °,该算法可用于需要对人体目标进行实时追踪的工程应用中,例如用于对人体目标实时跟随的移动平台或机器人中.     

新型飞秒激光跟踪仪中飞秒激光测距研究

飞秒激光频率梳的出现为研制新型飞秒激光跟踪仪提供了有利工具。为解决飞秒激光跟踪仪中高精度距离测量的问题,研究了飞秒激光光谱分辨干涉原理,使用钛蓝宝石飞秒激光器搭建实验系统对光谱分辨干涉进行实验验证,最后利用快速傅里叶变换方法对实验数据进行处理。实验结果表明:该测量方法可以实现精度为±5μm的距离测量,对新型飞秒激光跟踪仪中的测距研究具有指导意义。     

基于目标特征尺寸的可视化被动测距系统

为克服传统光电被动测距系统稳定性差、远距离条件下测距精度收敛性差、系统难以小型化等不足,本文提出一种基于目标特征尺寸的可视化光电被动测距系统。建立了被动测距模型并分析测距原理,从理论上分析获得距离反演公式和测距误差精度;设计了被动测距算法并分析相关成像参数获取途径和方法;通过高清成像器、半导体激光器和信号处理器等软硬件设计,实现了系统的可视化被动测距功能和全天候图像信息获取;最后通过目标特征尺寸及其成像系统参数反演目标距离,实现了在成像过程中实时测距并进行被动测距实验验证。实验结果表明,被动测距精度优于10%,当前软硬件参数配置下,目标的测距距离大于1km,测距鲁棒性好,性能稳定,可广泛应用于全天候目标图像信息获取和光电被动测距的实际工程实践中。     

基于iGPS的煤巷狭长空间中掘进机绝对定位精度研究

为解决目前掘进机定位方法中存在的非坐标化测量、自动化程度低、易被障碍物遮挡等问题,提出一种基于室内定位系统的掘进机定位方法。该方法将激光接收器安装在掘进机机身固定位置处,通过测量激光接收器在发射站坐标系下的三维坐标,实现对掘进机的绝对定位。基于随机误差建模理论推导双发射站坐标测量的误差传导公式;针对目前室内定位系统绝对测量精度检测方法在狭长空间应用中的局限性,结合测量精度理论分析结果,提出一种适用于狭长空间的绝对测量精度检测方法。实验数据表明,双发射站测量系统在1.2m间距下,发射站与掘进机相距17m时Y轴定位精度优于10cm,X、Z轴定位精度优于2cm。     

激光线投影技术在轨道车辆全位置焊接控制系统中的应用

为降低投影距离的定位误差，保证轨道车辆在焊接过程中的施工精度，基于激光线投影技术设计轨道车辆全位置焊接控制系统。设计光学反馈模块，确定机械光源、摄像机和镜头的结构参数；设计嵌入式平台，基于数据控制单元，实现数据的接收、连接、终止与处理。通过计算水平角与俯仰角的偏差值，自动建立轨道车辆焊接位置坐标系，计算激光投影误差，在旋转坐标下获取高斯分布的模版参数，实现激光线投影技术在轨道车辆全位置焊接控制系统中的应用。在实验中，对比4种不同焊接方法在X轴、Y轴、Z轴中对目标点的定位误差，结果表明，目标点的定位误差会随投影距离增加而增加，其中激光投影技术在投影距离不超过5 m时的定位误差均小于3 mm,可见该方法的控制精度较好。     

直接测距型无扫描激光主动成像验证系统

为提高成像效率,研究了基于雪崩光电二极管(APD)阵列和分束照明的直接测距型无扫描激光主动成像系统。系统采用脉冲激光器作为光源,通过测量激光脉冲飞行时间来获取目标距离信息;基于达曼光栅进行分束照明以提高能量利用率。另外,光学系统采用收发共孔径结构,保证了目标处激光脚点和APD阵列各像元的几何对准。与参考APD所采用固定阈值时刻鉴别法不同,系统采用固定阈值与恒比定时相结合的时刻鉴别法处理回波APD阵列的输出信号以适应外光路参数的变化。各通道采用专用计时芯片TDC-GP22测量启停脉冲之间的时间间隔,实现了45ps的计时分辨率。最后,将19m和31m处放置的两个角反射器作为合作目标进行了成像实验,并给出了所获取的距离图像。结果表明:两个目标的平均距离分别为19.28m和31.54m,测距误差分别为0.28m和0.54m,显示提出的设计方案切实可行。     

面向闸门门头运行轨迹检测的激光跟踪方法研究

船闸闸门门头运行轨迹是反映闸门运行状态的一项重要检测内容,目前主要依靠人工测量,无法实现在线检测。鉴于此,提出一种基于激光跟踪方法的闸门门头运行轨迹检测方法,构建二自由度激光跟踪测量系统,设计偏转和俯仰DD马达的PID控制器,进行系统的目标（靶镜）激光跟踪测试,结果表明该系统能实现运动目标的实时跟踪,跟踪重复精度优于80μm,跟踪速度达到16 mm/s,为闸门门头运行轨迹的检测提供了一种可行方法。     

基于 IGCF 算法和 CSF-PPSO-ESN 算法的工业机器人末端执行器位姿重复性检测

工业机器人在智能制造领域具有举足轻重的地位,其末端执行器位姿的重复性是衡量机器人完成精密作业能力的重要 指标。 本文针对机器人末端执行器的位姿重复性在线检测,提出了基于方向余弦的位姿重复性测量的理论模型。 设计了一种 基于改进的高斯曲线拟合(IGCF)算法和三次样条拟合-多目标粒子群-回声状态网络(CSF-PPSO-ESN)算法的位姿偏差检测方 法。 通过获取十字激光图像偏角和中心点位置,实现了机器人末端执行器位姿偏差的测量。 实验表明,测量系统的位移测量精 度为±1. 5 μm,角度测量精度为±2 arc-sec。 本文所述的位姿重复性检测方法,为工业机器人末端执行器位姿稳定性的在线实时 监测提供了参考。     

基于线结构光的盾尾间隙测量方法研究

针对现有盾构施工中盾尾间隙难以实时精确测量的问题,本文提出了一种基于线结构光的盾尾间隙自动测量方法。该方法首先利用线激光器在管片和盾壳之间投射出一道窄线型指示激光并通过工业相机实时采集线激光器投射在盾壳和管片之间的线激光图像,然后通过图像处理对图像目标特征进行识别并根据单目视觉成像原理和线结构光坐标测量算法提取盾尾间隙端点坐标,进而实现盾尾间隙值的精确解算。实验结果表明,本文所提出方法的重复性测量精度优于0.3 mm,绝对测量精度优于1.7 mm。该方法可以实现相机纵深方向0.2～1.9 m范围内盾尾间隙的实时精确测量,满足城市地铁隧道施工应用需求。     

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...     

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.     

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.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

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....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.