开放式数控线路板V型槽切割机的研制

基于开放式数控技术研制了线路板V型槽切割机;采用跳刀技术实现线路板不连续切割,采用固定销钉定位方法确保了高精度,独立数控Z及W轴线上锯切马达高度以保证锯切深度及残余厚度,通过程序自动坐标变换实现X Y连续切割,另外还有中断点保存和恢复、系统自动诊断等功能;叙述了V割机的机械结构,控制系统硬件组成,控制系统软件逻辑结构,主要软件模块以及AutoCad图形数据接口、抗干扰等关键问题的解决方法;样机运行结果表明机器精度高,切割速度快,运行可靠.     

AUTOCAD软件二次开发Hatch命令的实现——基于ObjectArx的开发

AutoCad2002及其后续版本的ObjectArx二次开发是面向对象程序发展的结果,在机械、建筑等领域有着广泛的应用,有巨大的市场需求。AutoCad命令的开发是二次开发中的一项重要内容。本文论述了hatch命令二次开发的设计过程和实现技术要点。     

计算机图纸与化工设备管理系统的设计与实现

文章从系统总体结构、功能设计、模块划分、关键实现技术以及系统的安全性等方面介绍了AutoCad图纸与化工设备管理系统的设计思想与实现技术,该系统采用OLE嵌入技术,实现了BLOB变量在数据库存取、网络传输以及在数据库应用程序中的图纸无级缩放,彻底解决了图纸的图形信息与信息系统的数据信息的无缝链接。     

一种汉藏双语句子对齐算法

双语语料库建设及其自动对齐研究对计算语言学的发展具有重要意义。双语对齐技术是加工双语文本的核心,对齐效果的好坏直接影响了以后工作的进行。基于汉藏双语的实际情况,提出了一种利用句子长度、相似度和锚点信息的汉藏双语句子对齐方法,该方法用相似度找到句子的锚点,用锚点将双语文本分割成几个分块,在对应双语分块中用基于长度的对齐实现句子的对齐。通过测试数据进行的实验结果显示,这种方法有着良好的准确率,有效地解决了汉藏双语真实文本的句子对齐问题。     

AUTOCAD软件二次开发Hatch命令的实现——基于ObjectArx的开发

AutoCad2002及其后续版本的ObjectArx二次开发是面向对象程序发展的结果，在机械、建筑等领域有着广泛的应用．有巨大的市场需求。AutoCad命令的开发是二次开发中的一项重要内容。本文论述了hatch命令二次开发的设计过程和实现技术要点。     

RFID系统中基于不精确锚点的移动用户定位方案

目前大多数基于RFID的移动用户定位算法使用锚点信息来 实现精确定位,然而许多情况下很难发现或部署足够多的锚点。为此,提出一种基于不精确锚点的移动用户定位方案。首先,使用大量带有粗略位置信息的标签作为锚点来计算用户的位置,此时不需要任何其他准确的锚点信息,有效避免了昂贵的锚点部署成本；然后,提出两种高时效算法来准确跟踪移动用户,即基于类别基数的协议和基于RSSI的协议。实验结果表明,改进的方法可实现移动用户的准确实时定位,该算法的精度比基准算法高30%以上。     

多策略汉维句子对齐

提出了一种错误抑制的多策略算法对齐汉维语句子。针对长度对齐算法无法避免错误蔓延的特点,提出了一种新的错误蔓延抑制策略:利用双语语料的词汇共现信息,自动抽取汉维语词汇搭配,结合句子长度特征,寻找1:1模式的句对作为锚点,将错误蔓延抑制在锚点内;在锚点之间,利用标点符号和长度混合方法进行句子对齐。算法实验结果验证了该多策略算法寻找的锚点的精度高,有效抑制了对齐错误的蔓延;采用的混合对齐算法,避免了基于词汇对齐算法的高时间复杂度的弱点,比传统的对齐算法性能有了较大提高,对齐准确率由95.0%提高到97.6%,召回率由96.8%提高到98.2%,采用的对齐正确性评价算法可以有效发现自动对齐中的噪音对齐。     

基于锚点类的GDA标准接口测试方法

介绍一种GDA标准接口的自动化测试方法。选择业务系统相关的锚点类．根据锚点类去除CIM模型中对业务系统无效的搓型,制定对业务系统有效的测试模型,分析测试数据,根据测试模型自动化生成测试的输入和期望输出．从而实现对GDA标准接口的自动化测试。与传统的测试方法相比,可适用于任意的CIM模型,任意的测试数据,随机生成测试的输入数据．保证测试的有效性、准备性及覆盖性。     

利用扩展锚点文本来分类网页

在以往一些分类方法的基础上，通过分析网页自身的结构，提出了一种利用扩展锚点文本来对网页进行自动分类的方法。     

传感器网络中一种分布式无锚点定位算法

确定节点的自身位置对自组织传感器网络具有重要价值.前人在假定网络具有若干锚点的前提下计算其他节点坐标,如果传感器网络没有配置锚点,则通常的定位算法难以执行.借助节点之间的测距值,引入虚拟锚点和定位可信度的概念,提出一种在节点处实现分布式无锚点定位的算法.针对定位期间的节点位置估算数值,结合邻接信息设计了一种位置变异策略,避免全网定位计算陷入局部最优解.实验结果表明,算法能有效解决无锚点网络的定位问题,在精度和全局能量比率等指标方面达到满意效果.     

基于MRAC 方法的直线电机的位置角度校正技术

分析了直线电机的位置角度误差对直线电机的输出电流的影响;为了消除直线电机的位置角度误差,作者在基于模型参考自适应控制方法的基础上设计了一套直线电机的位置角度校正系统.由于该校正系统中的位置角度误差补偿器采用不受位置角度影响的输入量对位置角度进行校正,所以可以在现有位置角度测量的基础上实现对位置角度的准确校正,为在现有直线电机和低精度光栅尺的情况下获得尽可能高的控制精度提供了保证.仿真和实验结果显示,采用位置角度校正后,直线电机可以实现对力矩电流的精确控制,而且位置角度误差能够被校正.     

Distributed consensus of second‐order multiagent systems with nonconvex input constraints

This paper addresses the input constrained consensus of second‐order multiagent systems with nonconvex constraints. A new update law is proposed to make the position states of all agents converge to a common point and the velocities converge to zero, while the input of each agent stays in a certain constraint set. The closed‐loop system is first converted to an equivalent system by taking a novel coordinate transformation. Then, it is proved that the input constrained consensus can be achieved if the graphs jointly have directed spanning trees by using the Metzler matrix theory. Finally, simulations are provided to demonstrate the effectiveness of the proposed algorithm.     

Concrete breakout strength of single anchors in tension using neural networks

A feed forward neural network model for evaluating the concrete breakout strength of single cast-in and post-installed mechanical anchors in tension is presented. The nodes of the neural network input layer represent the embedment depth, anchor head diameter, concrete strength and anchor installation system, and the neural network output is the tensile capacity of anchors as governed by the concrete breakout. Three different techniques have been adopted to represent the anchor installation system in the neural network input layer. The training, validation and testing of the developed networks were based on a database of 451 experimental tests obtained from previous laboratory anchor tests. Testing of the trained neural network indicates good predictions of the concrete breakout strength of cast-in and post-installed mechanical anchors in tension.The relationships between the concrete breakout strength of anchors and different influencing parameters obtained from the trained neural networks were in general agreement with those of the ACI 318-02 for cast-in and post-installed mechanical anchors. It has been shown that the concrete breakout strength of anchors in tension is approximately proportional to the embedment depth of 1.5 power and marginally affected by changing the anchor head diameter.     

一种采煤机组合定位系统及实验研究

综采工作面采煤机定位定姿技术,是液压支架跟机自动化和采煤机记忆截割的基础。采用捷联惯导监测采煤机姿态、速度及位置等运动参量,结合无线锚节点与移动节点间几何位置与局域信号对偶映射,建立了捷联惯导与无线传感器网络耦合模型,采用C＃＋MATLAB＋SQL交互式软件构建了采煤机组合定位系统,在采煤机、液压支架和刮板输送机“三机”平台上进行采煤机定位定姿性能研究。实验结果表明：捷联惯导能够有效地对采煤机姿态角度进行监测,但是长航时下采煤机位置存在累计误差,通过无线传感器网络位置对捷联惯导的位置进行周期性校正,组合定位系统下采煤机X和Y轴平均定位误差为0.118 m和0.268 m,能够得到采煤机实时可靠的位置和姿态。     

Robust detection and tracking of annotations for outdoor augmented reality browsing

A common goal of outdoor augmented reality (AR) is the presentation of annotations that are registered to anchor points in the real world. We present an enhanced approach for registering and tracking such anchor points, which is suitable for current generation mobile phones and can also successfully deal with the wide variety of viewing conditions encountered in real life outdoor use. The approach is based on on-the-fly generation of panoramic images by sweeping the camera over the scene. The panoramas are then used for stable orientation tracking, while the user is performing only rotational movements. This basic approach is improved by several new techniques for the re-detection and tracking of anchor points. For the re-detection, specifically after temporal variations, we first compute a panoramic image with extended dynamic range, which can better represent varying illumination conditions. The panorama is then searched for known anchor points, while orientation tracking continues uninterrupted. We then use information from an internal orientation sensor to prime an active search scheme for the anchor points, which improves matching results. Finally, global consistency is enhanced by statistical estimation of a global rotation that minimizes the overall position error of anchor points when transforming them from the source panorama in which they were created, to the current view represented by a new panorama. Once the anchor points are redetected, we track the user's movement using a novel 3-degree-of-freedom orientation tracking approach that combines vision tracking with the absolute orientation from inertial and magnetic sensors. We tested our system using an AR campus guide as an example application and provide detailed results for our approach using an off-the-shelf smartphone. Results show that the re-detection rate is improved by a factor of 2 compared to previous work and reaches almost 90% for a wide variety of test cases while still keeping the ability to run at interactive frame rates.     

一种分布式无线传感器网络节点定位新算法

针对无线传感器网络节点自身定位问题，提出一种新的节点定位算法，介绍算法的基本原理和实现方法。算法假设网络中有一定比例的锚节点（位置已知的节点）。通过未知节点和其无线射程范围内的锚节点之阃的通信约束和几何关系，得出该未知节点所处的圆弧区域，将该圆弧区域的质心作为未知节点的估计位置。该算法是一种完全基于网络连通性的无需测距技术的分布式算法，算法设计简单，计算量小。节点间通信开销少。仿真结果显示，该算法适合于各种规模的无线传感器网络的节点定位。     

Active vibration control of large space flexible slewing truss using cable actuator with input saturation

This paper proposes a composite approach to implementing attitude tracking and active vibration control of a large space flexible truss system. The system dynamic model is based on Hamilton's principle and discretized using the finite difference method. A nonlinear attitude controller for position tracking is developed based on the input‐output linearization of the discretized system, which can effectively improve system performance compared with a traditional proportional‐differential feedback controller. A taut cable actuator scheme is presented to suppress tip vibration because the mechanical model is a large large‐span spatial structure; furthermore, because the cable has the feature of unilateral input saturation constraint, which can provide only a pulling force, a nonlinear quadratic regulator controller is developed by introducing a piecewise nonquadratic cost function to suppress the vibration of the flexible structure. To investigate the factors that influence the damping effects of the cable, the parametrically excited instability of a cable under 2 supports is analyzed. Simulation results illustrate that the proposed attitude controller can implement the task of position tracking, and the vibration suppression control law is shown to be optimal for functional performance with input saturation.     

基于分散神经网络的多指灵巧手位置控制

针对多指灵巧手钢缆传动系统的非线性，提出一种基于分散神经网络的位置控制方法．通过 对复杂的钢缆传动系统施加不同的输入可以得到特定的相对简单的输入输出数据，利用这种 特定的输入输出数据学习传动系统的非线性关系得到多个分散的神经网络，再根据传动系统 的结构特性用分散的神经网络求取钢缆传动系统的逆模型，用于直接逆控制，从而达到补偿 非线性误差的目的．同时应用在线神经网络的适时补偿使系统长时间保持良好的运行状态． 实验证明这种方法可大大提高位置跟踪精度，取得比较满意的结果．     

基于RSSI加权质心和GASA优化的WSN定位算法

针对无线传感器网络节点在自身定位中广泛存在较大的定位误差的问题,提出一种基于RSSI加权质心和GASA优化的无线传感器网络定位算法。该算法假设无线传感器网络中存在一定比例的位置已知的锚节点,利用RSSI加权质心算法计算未知节点与锚节点间的距离,建立以未知节点位置为参数的数学模型,用GASA优化算法计算最优解从而获得未知节点的位置,实现未知节点自身的定位。仿真实验的结果表明,当锚节点个数为30,算法的平均定位误差在10%以内,比RSSI加权质心算法降低了10%~15.5%左右,并且随着节点个数的增加平均定位误差降低。     

A new approach to improve absolute positioning accuracy of robot manipulators

This article describes a new calibration system for robot manipulators which improves their absolute positioning accuracy by using parameter-estimation algorithms based on the Newton method. When 3D position data of the specified points on a manipulator and the joint encoder values are input to the calibration system, the system estimates the offset values of joint encoders, link lengths, and position and orientation of the manipulator base coordinate system with respect to the world coordinate system which is difficult to obtain by conventional calibration methods. This calibration system can be applied to various manipulator types by just changing the basic kinematic equations. The system employs an algebraic programming system called REDUCE to automatically reduce the manipulator kinematic equation and partial differential calculus in the Newton method. For efficiency, first only the arm part with three degrees of freedom and then the hand part are calibrated. The experimental results demonstrate the effectiveness of this system by reducing the robot's absolute positioning errors to the order of repeatability errors.