飞行器供配电系统通用测试方案设计

供配电测试设备中专用设备比例仍较高,导致研制费用高,使用维护不便,操作人员需熟悉各种设备,人员培训也形成了困难;通过飞行器通用测试需求分析,结合某项目供配电测试系统方案,提出设备通用、软件可二次编程的设计方案;通用性测试方案减少了专用设备数量,降低研制费用,提高使用效率,有利于提高设备继承性和互换性,实现供配电测试系统高可靠设计;经过通用化设计,设备功能满足设计要求,指标显著提高,且满足后续项目需求;最后展望了飞行器测试系统的技术发展和应用前景。     

基于惯量辨识的测试转台自适应内模控制

为了降低系统模型参数变化对测试转台控制系统的影响,提出了基于惯量辨识技术的自适应内模控制方案.首先建立了某型号测试转台数学模型,设计了测试转台内模控制器,在此基础上采用基于扰动转矩观测器的惯量辨识算法来辨识测试转台转动惯量的变化情况,然后通过模糊控制器根据转动惯量的变化自动调整内模控制器的参数,从而确保了控制器的控制性能.仿真和实验结果表明,该控制方案对惯量的变化有着很强的自适应性,提高了测试转台控制系统的抗干扰性能和系统的鲁棒性,取得了较好的控制效果.     

程控双轴姿态转台伺服控制系统设计及应用

针对自主研发的程控双轴姿态转台伺服控制系统,阐述了其运动控制系统的基本工作原理;针对传统转台转速慢、精度差、系统动态性能和稳定性不佳等问题,设计了基于位置环、速度环和电流环三闭环控制的数字控制器;完成了控制系统控制算法的软件实现,利用LabWindows CVI交互式编程平台研发了转台控制软件,可以对串口设置、PID设置、驱动器设置等参数进行任意更改,使系统操作简便、可移植性强;最后对系统开展位置和速度跟踪性测试,测试结果表明系统性能达到预期,具有超调小、响应快、跟踪精度高和鲁棒性好等特点,满足系统设计要求,具有良好的应用价值。     

飞行仿真转台的软件控制系统设计

飞行仿真转台作为航空、航天领域中进行半实物仿真和测试的关键设备,在飞行器的研制过程中起着非常关键的作用。以五轴飞行仿真转台为研究对象,介绍了系统的软硬件平台设计体系,然后根据软件控制系统的基本原则,采用模块化设计,以通用性、安全性为出发点,采用面向对象的程序设计思想,分别从模式选择、实时显示、数据保存、精度补偿、状态监控、安全保护和网络通讯等7个方面阐述了其设计思想。该系统经过实际的联机测试和控制实验,证明稳定可靠,界面友好,达到了理想的效果。     

一种基于MFC的转台自动测试系统

三轴转台在惯性测量组件和惯性导航系统的性能测试中起到了重要作用,而原先的转台标定实验需要测试人员通过上位机操纵转台运动到指定位置和速率状态,并手动操纵远程计算机采集惯性导航组件的实验数据.采用VC++中的MFC形成远程控制计算机界面,通过远程控制计算机直接控制三轴位置速率转台,并自动采集惯性导航组件的测试数据.经过远程控制计算机与转台形成闭环实验,测试系统可以完成预期目标.     

卫星姿态控制系统的地面模拟转台

一、概述为了满足卫星姿态控制系统和各种敏感器动、静态性能测试及地面模拟的需要,我所集中了一定的力量,对卫星姿态腔制地面模拟设备及目标模拟器进行了研制,已积累了廿年的经验。地面模拟转台是卫星控制系统仿真的关键性的设备之一。它的研制难度较大,涉及的技术面宽,设备规模亦比较大。目前我所研制的电动转台在国内有较高的水平,某些设备已接近或达到国外同类转台的水平。     

一种改进的等精度转台角速度测试方法的实现

目前转台角速度测量主要利用长时间求平均值的方法，测量时间较长，不能实时测量，本文提出改进等精度法测量方法测量转台的角速度，采用FPGA快速测频技术实现了转台角速度实时测量。研制了便携式转台角速度测试系统，代替以往用来进行角速度测量的大型数字频率计等设备。用虚拟仪器搭建人机交互平台，实现转台角速度的实时处理，对数据进行快速高效的采集、分析、显示、存储，代替以往的人工录入再进行数据处理的方法，实现了转台角速度现场、快速测试。     

基于模型的转台系统故障检测方法

研究了飞行模拟转台的建模与故障检测问题.飞行模拟转台不仅是导弹制导回路半实物仿真闭环系统中的一个环节,也是一个反馈控制系统,转台内部参数与仿真系统中的各种参数相互影响,导致故障传递特性复杂,无法简单的根据转台参数测试判断转台运行状态.根据转台系统的跟踪特性,提出了基于模型的转台系统故障检测方法.由于传统的转台建模方法存在建模困难、精度不高的问题,因此采用系统辨识方法,通过辨识实验的设计,借助Matlab软件系统辨识工具箱进行模型的辨识,建立了转台系统三个框架的数学模型,利用相同输入条件下的数学模型输出和实际系统输出之间的残差变化,对转台运行情况进行检测,较好的解决了转台系统的故障检测问题.通过对三种转台故障的检测,验证了改进方法的有效性.     

测试转台的自抗扰控制器设计

工程上通常采用经典控制方法对测试转台进行控制,但往往很难保测量结果的高精度和强抗扰性。本文用自抗扰控制器来控制测试转台。仿真结果表明系统响应快,超调小,精度高,抗扰能力强,最后与经典控制的对比,进一步证明了自抗扰控制器是适用于测试转台控制的理想控制器。     

七自由度测试转台的控制系统设计

对于航空飞行器等设备,在实际运行前可通过多自由度测试转台对其进行动态性能分析,以获得理想控制效果;以七自由度航空设备测试转台为研究对象,采用开放式结构形式和通用外围设备建立系统硬件平台,以VC++为开发工具设计了控制系统的软件结构;为了保证该转台的可靠性,利用OpenGL建立了三维物理模型的虚拟运动仿真系统,进行控制指令的虚拟运动仿真,发现可能的运动干涉,有效避免错误指令;经过试验验证,该系统稳定可靠,达到预期的控制效果.     

Robust similarity registration technique for volumetric shapes represented by characteristic functions

This paper proposes a novel similarity registration technique for volumetric shapes implicitly represented by characteristic functions (CFs). Here, the calculation of rotation parameters is considered as a spherical cross-correlation problem and the solution is therefore found using the standard phase correlation technique facilitated by principal components analysis (PCA). Thus, fast Fourier transform (FFT) is employed to vastly improve efficiency and robustness. Geometric moments are then used for shape scale estimation which is independent from rotation and translation parameters. It is numerically demonstrated that our registration method is able to handle shapes with various topologies and robust to noise and initial poses. Further validation of our method is performed by registering a lung database.     

Transformation parameter estimation using parallel output based neural network

One of the challenging tasks in image registration is to estimate transformation parameters automatically and efficiently. In this paper, we propose a task decomposition based parallel trained neural network to estimate transformation parameters as well as order of transformations. This parameter estimation problem can be divided into several subproblems like rotation, translation and scaling estimation. Each subproblem or module consists of decomposed input datasets, as well as a part of the output vector. Each module is trained in parallel for some specific and fixed input–output vector pattern. Feature vectors are used as input dataset of the proposed neural network. 2D PCA (two dimensional principal component analysis) feature extraction technique is used to build feature vector. This modular technique requires effectively less computation time in comparison to non-modular network. Moreover, this technique can robustly estimate different transformational parameters. The added advantage of this technique is that it can identify order of the transformation. Experimental results justify the effectiveness of the proposed technique.     

Error analysis of pure rotation-based self-calibration

Self-calibration using pure rotation is a well-known technique and has been shown to be a reliable means for recovering intrinsic camera parameters. However, in practice, it is virtually impossible to ensure that the camera motion for this type of self-calibration is a pure rotation. In this paper, we present an error analysis of recovered intrinsic camera parameters due to the presence of translation. We derived closed-form error expressions for a single pair of images with nondegenerate motion; for multiple rotations for which there are no closed-form solutions, analysis was done through repeated experiments. Among others, we show that translation-independent solutions do exist under certain practical conditions. Our analysis can be used to help choose the least error-prone approach (if multiple approaches exist) for a given set of conditions.     

基于平面镜的摄像机内参数线性标定方法

提出了一种全新的基于平面镜的摄像机标定方法。该方法无需任何标定物,利用平面镜的反射性质和灭点、灭线等理论,通过移动摄像机或平面镜作至少2次平移运动(各次平移间应存在旋转运动)即可线性地标定摄像机的内参数。模拟图像实验和真实图像实验表明所提出的方法能快速、方便地对摄像机进行标定,具有较好的稳定性和精度。     

A camera calibration technique using three sets of parallel lines

This paper presents a new method for three-dimensional camera calibration in which the rotation parameters are decoupled from the translation parameters. First, the rotation parameters are obtained by projecting three sets of parallel lines independently of the translation parameters and the imaging distance from the lens to the image plane. The virtual line passing through the image center, which is calculated by perspective projection of a set of parallel lines, depends only on the rotation parameters. Next, the translation parameters and the imaging distance are analytically obtained. Experimental results are used to show how the camera model can be accurately reconstructed in an easily prepared environment.     

A frequency domain technique for range data registration

This work introduces an original method for registering pairs of 3D views consisting of range data sets which operates in the frequency domain. The Fourier transform allows the decoupling of the estimate of the rotation parameters from the estimate of the translation parameters, our algorithm exploits this well-known property by suggesting a three-step procedure. The rotation parameters are estimated by the first two steps through convenient representations and projections of the Fourier transforms' magnitudes and the translational displacement is recovered by the third step by means of a standard phase correlation technique after compensating one of the two views for rotation. The performance of the algorithm, which is well-suited for unsupervised registration, is clearly assessed through extensive testing with several objects and shows that good and robust estimates of 3D rigid motion are achievable. Our algorithm can be used as a prealignment tool for more accurate space-domain registration techniques, like the ICP algorithm.     

基于三维模型和仿射对应原理的人脸姿态估计方法

该文提出了一种基于人脸三维模型和仿射对应原理从单目视频图像序列中估计人脸空间姿态的方法．其主要思想是利用人脸的三维模型生成特征点正面平行投影,并估算输入帧和该正面平行投影之间的仿射变换参数,然后根据圆一椭圆之间的仿射对应关系得到描述人脸空间姿态的6个参数(3个旋转分量,3个平移分量)的粗略估计值,最后通过基于ICP(Iterative Closest Points：反复最近点)算法的优化迭代过程得到精确值．对石膏像和真实人脸进行的实验结果表明该算法能在较大的姿态变化范围内实现精确的人脸姿态估计．     

Determination of three-dimensional object location and orientationfrom range images

A technique for determining the distortion parameters (location and orientation) of general three-dimensional objects from a single range image view is introduced. The technique is based on an extension of the straight-line Hough transform to three-dimensional space. It is very efficient and robust, since the dimensionality of the feature space is low and since it uses range images directly (with no preprocessing such as segmentation and edge or gradient detection). Because the feature space separates the translation and rotation effects, a hierarchical algorithm to detect object rotation and translation is possible. The new Hough space can also be used as a feature space for discriminating among three-dimensional objects     

基于平面激光测量的移动机器人自定位方法

提出了两种基于平面激光测量的移动机器人自定位方法. 第一种方法是改进的Hough 密度谱的方法, 它的主要优点是避免了现有方法Hough 变换离散化过程中的信息损失问题，提高了算法的精度和鲁棒性. 该方法在引进一种新的Hough 密度谱的基础上，根据谱相关函数值和运动参数的密度得到机器人运动参数的候选值，并应用Hausdor 相似性度量从候选值确定运动参数的最终估计. 第二种方法是基于Fourier-Mellin 变换的方法，主要利用Fourier 变换的位移理论和Fourier-Mellin不变量来估计运动参数. 为了避免图像离散化造成的信息损失，在该方法中使用基于Hausdor 距离的最近点迭代(ICP) 算法来进一步精化平移向量. 实验结果表明，这两种方法均可有效地提高机器人的定位精度，具有一定的实际应用价值.     

The shape-oriented dissimilarity of polygons and its application to the classification of chromosome images

Pavlidis in his “analysis of set patterns” proposed three size-oriented similarity measures. In this paper, shape-oriented similarity and dissimilarity measures of triangles and polygons are proposed and investigated. There are three advantages of shape-oriented similarity measures. First, two polygons may have the same shape but differ in area and dimensions and still be similar. Second, shape-oriented similarity and dissimilarity measures can be normalized between zero and one. Third, shape-oriented similarity measures are invariant with respect to rotation, translation, or expansion or contraction in size. The “rubber-mask” technique proposed by Widrow utilized length and width parameters in the classification of chromosomes. In this paper, chromosome images are classified through the use of angular and dimensional proximity measures which are in terms of angle and length parameters. The results obtained in this paper may contribute to processing a picture from the polygonal approximation stage to the final filtering stage in order to recognize or classify a picture.