旋转飞行体横滚角高精度测量研究

利用我国自行研制的低漂移角速率陀螺敏感飞行体旋转角速率,其输出送给积分器进行积分运算,并由地磁方位变换器给出积分归零信号,消除了积分积累误差。在旋转角速率≤1080°/s条件下,工作时间1.5～4min,实测横滚角精度优于万分之一,可达十万分之四(工作时间99s测试结果)。     

基于三维空间的刚体位姿测量分析与仿真研究

本文针对刚体在三维空间中的位姿测量问题及数据可靠性的需求,提出一种基于三维空间的刚体位姿测量分析方法。首先,对位姿测量装置的结构进行分析,采用基于3-2-1六点定位原理的位姿测量算法,对刚体位姿坐标系建模,并求解相应的位姿关系式,利用实体设备,对位姿测量装置进行测量精度分析。结果表明：该方法在位置和姿态上符合实际情况,满足工业生产的测量精度要求,具有较好的稳定性和准确性。     

基于物体表面形貌的单相机视觉位姿测量方法

为了获取在风洞实验中运动物体的位姿变化,提出了一种融合物体表面三维形貌信息的单相机视觉位姿测量方法。该方法以多点透视成像原理作为求解物体位姿变化的基础,以物体的图像特征角点作为特征点,并利用物体表面三维形貌模型信息获得特征点的三维坐标。通过实验完成了该测量方法的精度验证,在400 mm的观察距离上,位移平均测量误差为0.03 mm,均方根误差为0.234 mm;俯仰角、偏航角与滚转角的平均误差分别为0.08°、0.1°与0.09°,均方根误差分别为0.485°、0.312°与0.442°。实验结果表明该方法有可用于实用的测量精度。

     

多边法位姿测量系统中跟踪方式对测量精度的影响研究

为了精确测量大尺寸位姿,建立了一种由7台激光跟踪干涉仪组成的大尺寸位姿测量装置。根据测量各反射镜的激光跟踪干涉仪数量的不同,采用322和331两种跟踪方式对位姿测量精度的影响进行仿真实验,从而发现被测点位置与基站构成平面的距离相关,由坐标解算公式推导被测点坐标值与测量基站之间的相对位置与测量误差间的误差模型,通过分析x、y、z 方向上误差对距离变化的敏感程度,发现z方向距离变化引起的误差最为敏感。当被测点与测量基站的距离由1300.8mm减小到0mm时,测量误差由2.2μm增大到2626.1μm。实际姿态测量结果表明:当采用一种跟踪方式时可以避免被测点与测站点平面过近,有利于提高系统测量精度,所提出的误差模型可为多边法位姿测量系统的优化布局提供一种量化的理论分析方法。     

多摄像机传递位姿测量系统的软件设计与实现

传统的摄像测量技术用于测量物体三维位姿及其变形时,通常只能应用于可通视的物体之间或处于同一个视场的物体之间.多摄像机接力传递位姿测量通过接力传递的方式,可以实现对大型结构体中不通视物体之间或大视场范围内物体之间的位姿及其变形进行测量.本文首先对多摄像机接力传递位姿测量方法的基本原理进行了阐述;然后,通过对其硬件结构特点进行分析,提出了相应的软件功能模块与程序控制流程;最后,按照经典的"客户机-服务器"模式分别开发设计了分机软件和主机软件,并用Visual C++语言予以实现.经过大量室内.、室外及海上实船实验证明,该软件系统操作简单,使用方便,运行稳定可靠,可扩展性较强.     

复杂光照环境下空间目标相对位姿测量方法研究

为解决空间复杂光照环境下可见光相机获取的图像照度不一、信息失真、特征不完整导致的目标 航天器相对位姿求解困难的问题,提出了一种基于图像增强和弧段特征的双目视觉相对位姿测量方法。首先通 过基于带色彩保留的多尺度Retinex（Multi?scale Retinex with Chromaticity Preservation, MSRCP）自适应图像预处理 方法提升空间暗弱光、局部强曝光环境下的图像质量;然后利用基于边缘弧支撑线段的椭圆检测算法提取目标 航天器表面星箭对接环的弧段特征,并拟合得到椭圆轮廓;最后利用双目相机搭建了空间相对位姿测量物理仿 真实验平台,建立双目空间椭圆锥测量模型解算目标的六自由度相对位姿,实现了近距离正常光照和暗弱光照 场景下目标航天器相对位姿求解。实验结果显示：在正常光照场景下,相对位置平均误差优于20 mm,相对姿 态平均误差优于0. 3°;在暗弱光照场景下,相对位置平均误差优于30 mm,相对姿态平均误差优于1°。研究成 果为近距离空间交会对接等在轨服务任务中的目标识别与测量提供了参考,具有技术借鉴价值。     

ICF实验中靶位姿的视觉检测

惯性约束核聚变(ICF)实验中,靶定位精度直接影响打靶的成功率.本文利用三个CCD从不同的视角得到靶的图像,综合三个CCD的特征值计算靶的空间坐标和方位旋转矩阵,从而确定其在空间的六维位姿.对于特征值的提取,本文采用“模板匹配”和“椭圆轮廓拟合”相结合的数据融合图像处理技术,并利用双立方插值法实现了亚像素的测量精度,从而使微型靶的定位精度达到了微米级.实验结果表明,该检测方法稳定性好,定位的重复性误差小于1μm且获得了优于2 μm的测量精度.     

基于锥孔靶标的机器人末端位姿间接测量方法

机器人的位姿误差是衡量机器人性能的重要指标,因此位姿测量是机器人校准过程中的重要环节。为简化机器人末端位姿测量过程,提出一种间接测量方法。首先设计靶标并建立靶标坐标系、将靶标安装在法兰盘上、标定出两者之间的转换关系;然后利用绝对关节臂测量机测量靶标上的锥孔,采用最小二乘法并结合靶标坐标系与法兰盘坐标系之间的转换矩阵计算出机器人末端位姿,并分析测量误差对位姿误差的影响;最后对KR5arc工业机器人末端位姿进行测量。实验表明:该间接测量方法相较于直接测量方法的优点在于不仅可以保证测量结果的准确度,而且可提高测量结果的紧密度、大大简化测量过程。     

无位姿约束的线激光视觉传感器参数标定

针对现有线激光单目视觉传感器参数标定方法中靶标移动需要精密机械控制或可自由移动靶标摆放位姿受约束等不足,提出一种靶标可自由移动且摆放位姿无约束的新标定方法.根据靶标特征点的成像点所构成向量簇的叉积方向集合的射影不变性,对成像点排序,建立靶标特征点与其成像点的对应关系;由光刀中心拟合直线与靶标特征点的成像点所构成包络求交,提取光平面特征点,并根据交比不变原理计算其三维坐标;最优化拟合计算单目摄像机内外参数及线激光投射器光平面参数,实现传感器参数的精确标定.试验表明,该标定方法操作自由、步骤简便,具有较理想的标定精度.     

地磁旋转弹滚转角及角速率的估计方法

针对高转速的旋转弹等制导弹药滚转角及滚转角速率实时获取的问题,提出一种基于地磁信息的滚转角及滚转角速率的实时快速估计方法.首先根据旋转弹的轴向滚转运动特性,利用卡尔曼滤波算法实时估计弹丸在轴向高速旋转的状态下的滚转角以及角速率,考虑弹载实时应用需求,在卡尔曼滤波的基础上进一步采用α-β-γ滤波来提高估计算法的实时性.通...     

基于P3HT的有机太阳能电池的特性研究

聚3已基噻吩（P3HT）是近年来出现的一种新型有机聚合物太阳能电池的供电子体材料。通过真空蒸镀与旋涂相结合的方法,制备了基于聚合物P3HT的结构为ITO/Buffer layer/P3HT/C60/Bphen/Ag的有机太阳能电池。测试结果表明P3HT、C60的优化厚度分别为30、40nm。如果还引入金属氧化物MoO3作为阳极缓冲层,能够明显地提高电池的开路电压,其中MoO3阳极缓冲层的优化厚度为1nm。因此,通过优化制备工艺、引入新的器件材料,能更理想地调控太阳能电池的性能参数。     

Influence of P2O5 on the formation and hydration properties of C4A3S_

The influence of P₂O₅ on the formation and hydration properties of C₄A₃S_ has been studied here. Results show that the forming rate of C₄A₃S_ is decreased by the stabilization of P₂O₅ to the transitional resultant CA at 1300 °C for one hour; when soaking time is increased to three hours, adding a suitable amount of P₂O₅ can promote the forming content of C₄A₃S_, but if the amount of P₂O₅ is more than 1%, the forming content of C₄A₃S_ reduces. P₂O₅ will result in the tetragonal system structure of C₄A₃S_. At this experimental condition, adding a suitable amount of P₂O₅ can increase the hydration activity of C₄A₃S_ attributing to the distortion in the crystal lattice of C₄A₃S_. Received: 16 September 1999 / Reviewed and accepted: 15 March 2000     

Maximum roll angle estimation of a ship in confused sea waves via a quasi-deterministic approach

This paper considers the maximum roll motion of a ship in confused sea waves. The ship motion is described by a nonlinear differential equation including quadratic damping and cubic restoring force. The excitation of the ship is represented by a stationary mean-zero Gaussian process of a given power spectral density function. It is shown that a reliable estimate of the maximum roll motion is found considering the ship response to an approximate deterministic representation of an appropriately large and adequately rich (frequency-wise) load. Specifically, the time variation of the load is approximated by a normalized autocovariance function; the maximum amplitude of the load is taken as a certain multiple of the standard deviation of the stochastic load process. This approximation relates to the method of quasi-deterministic representation of extreme realizations of a stationary Gaussian process; the method is interpreted as a tool for generating deterministic time histories of the load which are compatible with a certain power spectral density function. The efficacy of this perspective is shown by comparison with the results from pertinent Monte Carlo simulations.Next, the paper addresses the ship stability problem in the space of initial conditions. In this context, it shows that the proposed approximation can be adequately utilized for a ship safety assessment.     

Fringe inverse videogrammetry based on global pose estimation

Fringe inverse videogrammetry based on global pose estimation is presented to measure a three-dimensional (3D) coordinate. The main components involve an LCD screen, a tactile probe equipped with a microcamera, and a portable personal computer. The LCD is utilized to display fringes, a microcamera is installed on the tactile probe, and the 3D coordinate of the center of the probe tip can be calculated through the microcamera's pose. Fourier fringe analysis is exploited to complete subpixel location of reference points. A convex-relaxation optimization algorithm is employed to estimate the global camera pose, which guarantees global convergence compared with bundle adjustment, a local pose estimation algorithm. The experiments demonstrate that fringe inverse videogrammetry can measure the 3D coordinate precisely.     

Probabilistic 3D object recognition and pose estimation using multiple interpretations generation

This paper presents a probabilistic object recognition and pose estimation method using multiple interpretation generation in cluttered indoor environments. How to handle pose ambiguity and uncertainty is the main challenge in most recognition systems. In order to solve this problem, we approach it in a probabilistic manner. First, given a three-dimensional (3D) polyhedral object model, the parallel and perpendicular line pairs, which are detected from stereo images and 3D point clouds, generate pose hypotheses as multiple interpretations, with ambiguity from partial occlusion and fragmentation of 3D lines especially taken into account. Different from the previous methods, each pose interpretation is represented as a region instead of a point in pose space reflecting the measurement uncertainty. Then, for each pose interpretation, more features around the estimated pose are further utilized as additional evidence for computing the probability using the Bayesian principle in terms of likelihood and unlikelihood. Finally, fusion strategy is applied to the top ranked interpretations with high probabilities, which are further verified and refined to give a more accurate pose estimation in real time. The experimental results show the performance and potential of the proposed approach in real cluttered domestic environments.     

Influence of P3HT concentration on morphological, optical and electrical properties of P3HT/PS and P3HT/PMMA binary blends

Poly(3-hexylthiophene) (P3HT) has interesting optoelectronic properties and a wide variety of applications such as solar cells and O-FET devices. It is a soluble conductive polymer but their mechanical properties are poor and its conductivity is unstable in environmental condition. With the finality of overcome these disadvantages, P3HT binary blends with two insulating polymers, polystyrene (PS) and polymethylmetacrilate (PMMA), have been synthesized by direct oxidation of 3-hexylthiophene with FeCl₃ as oxidant inside the insulator polymers. Molecular weight and polydispersity of P3HT polymer were measured by size exclusion chromatography and the degree of regioregularity by ¹H RMN. P3HT/PS and P3HT/PMMA thin films were prepared by spin-coating technique from toluene solution at different P3HT concentrations. The doped films were obtained by immersion during 30 s in a 0.3 M ferric chloride (FeCl₃) solution in nitromethane. A classical percolation phenomenon was observed in the electrical properties of the binary blends, it was smaller than 4 wt.% of P3HT in the blend. Atomic force microscopy and confocal microscopy showed a phase-separated morphology. Variation in the surface morphology of the blends was observed, which was a function of the polymer concentration and the type of insulator polymer used in the blends. The insulator polymer was segregated on the surface of the films and showed pit and island-like topography. The pit and island size changed as a function of the polymer concentration. Optical absorption properties as a function of the P3HT concentration in the undoped and doped state were analyzed. In doped state, the bipolaron bands in the PS/P3HT and PMMA/P3HT blends were observed from a P3HT concentration of 1 wt.% and 3 wt.%, respectively. Finally, the polymers were analyzed by thermogravimetric analysis and infrared spectroscopy.     

82MnA钢连铸坯中的磷化物Fe3P分析

在对82MnA钢连铸坯进行常规金相检验时发现,其显微组织中有沿晶界分布的白色相,采用直读光谱仪、光学显微镜、显微硬度计、扫描电镜及X射线能谱仪等仪器对这种白色相进行了测试和分析。结果表明:82MnA钢连铸坯中的白色相为磷含量较高的磷化物Fe₃P,其硬度较高,大多沿晶分布,具有明显的边界和液态随意凝固特征,危害性较大。     

Quasi-ordered P3HT nanopillar-nanocap structures with controlled size

A fast and cost-effective technique is applied for fabricating an innovative nanostructure based on Poly(3-hexylthiophene). Such nanostructure consists of nanopillar arrays on a substrate of hexagonally quasi-ordered nanocap arrays of the same polymer. In this fabrication process, hybrid nanoporous anodic alumina fabricated by applying an asymmetric anodization process is used as template. The resulting nanostructure is replicated from the template via spin-coating and melt-assisted wetting methods. In addition, such nanostructure can be fabricated with a large quantity of structural configurations and materials. As a result of this versatility, it would be possible to use this nanostructure for fabricating a new kind of ordered bulk-heterojunction solar cells with enhanced efficiency.     

Effect of cadmium sulphide quantum dot processing and post thermal annealing on P3HT/PCBM photovoltaic device

The present study demonstrates the effect on photovoltaic performance of poly(3-hexylthiophene) (P3HT) on doping of cadmium sulphide (CdS) quantum dots (QDs). The P3HT/CdS nanocomposite shows a 10 nm blue shift in the UV-vis absorption relative to the pristine P3HT. The blue shift in the absorption of the P3HT/CdS nanocomposite can be assigned to the quantum confinement effect from the CdS nanoparticles. Significant PL quenching was observed for the nanocomposite films, attributed to additional decaying paths of the excited electrons through the CdS. Solar cell performance of pure P3HT and dispersed with CdS QDs have been studied in the device configuration viz indium tin oxide (ITO)/poly(3,4-ethylendioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS)/P3HT:PCBM/Al and ITO/PEDOT:PSS/ P3HT:CdS:PCBM/Al, respectively. Incorporation of CdS QDs in the P3HT matrix results in the enhancement in the device efficiency (?) of the solar cell from 0.45 to 0.87%. Postproduction thermal annealing at 150 °C for 30 min improves device performance due to enhancement in the device parameters like FF, V_OC and improvement in contact between active layer and Al.