A new visual method for inner-diameter of pipe figure components

In order to measure the inner-diameter of pipe figure components rapidly and efficiently, a new high accurate method based on computer vision was introduced. The new visual measurement method was comprised of two phases, which were capturing cloud data of generatrix and processing cloud data of generatrix. The first phase employed the LMS (Laser Multi-spots Scanning) method, which combined the merits of the LSS (Laser Single-spot Scanning) method, the IRLS (Integrated Ringy Laser Section) method, the DRLS (Distributed Ringy Laser Section) method and the DRDL (Distributed Ringy Discrete Laser-spot) method, and overcame the faults of these methods. The second phase introduced the generatrix resample technology and the symmetrical generatrix difference technology. In this paper, the visual measuring arm based on the LMS method was designed in the beginning. Then, according to the optical structure of the visual measuring arm, a 3D real time mathematic model was developed. Lastly, the data processing technology proposed was adopted to process the cloud data of generatrix. The measurement system based on the new method could complete the measurement of inner-diameter of pipe figure components rapidly and efficiently in experiments, demonstrated good stability, and got high precision. The article is published in the original.     

基于适应性装配特征的自动装配技术研究

装配设计是现代CAD技术中的一个重要组成部分,但其中对零部件自动装配的研究还相对薄弱。笔者在研究参数化设计和装配建模的基础上,提出了基于适应性装配特征的零部件自动装配方法,根据适应性装配特征来确定零部件间装配关系和装配对象的主参数,以便适应调整装配对象姿态、完成自动装配、提高装配设计的速度和效率。根据以上研究开发的基于CATIA平台的导管焊接夹具自动装配模块,验证了该方法的有效性和实用性。     

激光跟踪运动物体空间坐标测量系统研究

基于激光跟踪干涉测量法建立的柔性三坐标测量系统能够有效地解决运动物体 (如机器人手臂、数控机床刀具 )空间位置测量 ,并且有望获得高的精度。讨论了球坐标法激光跟踪干涉动态测量 ,给出了测量原理和系统构成 ,建立了数学模型和实验。     

相交双管焊接坡口的数据化处理

运用空间解析几何知识建立了相交双管焊接装配时，沿径向切割的支管与非切割的主管密闭准确安装的数学模型，给出了相交双管相贯线的参数方程，导出了相交双管相贯线上各点局部二面角的计算表达式。以此为基础开发了相交双管焊接坡口的数据化处理系统。该系统可计算出相交管子焊接装配所需要的所有参数。实管切割实验表明，所切支管与主管装配准确，焊接坡口各参数完全符合AWS D1．1规范的要求。     

气液环状流周向液膜测量传感器的优化设计

以气液两相环状流管道横截面的周向液膜为测量对象,采用单台高速摄像机和平面反射镜组构建了虚拟双视角的视觉传感器,并对传感器进行了优化。基于虚拟双目立体视觉原理建立虚拟双视角视觉传感器测量模型。为了尽可能增大有效拍摄视角以获得更多液膜流动信息,综合考虑视场区域、传感器尺寸、测量距离以及管道光路折射等因素,对虚拟双视角视觉传感器模型进行了分析和设计,优化了传感器模型的结构参数。理论分析及实验结果表明:优化后的虚拟双视角视觉传感器可以获得近300°的有效周向测量视角,远远优于使用单台高速摄像机进行直接拍摄。该项研究为通过双视角视觉传感器进行气液两相环状流周向液膜的实时测量提供了理论基础,对研究液膜厚度和分析环状流流动状态具有重要意义。     

用速度-差压法对送粉管道煤粉浓度测量模型的研究

基于垂直上升管中气固两相流支时气固质量比与差压和流速之间的理论关系,针对能源工业中电厂锅炉燃烧系统送粉管道进行了速度－差压法测量煤粉浓度的试验研究,得出了相应测量送粉管道中煤粉浓度的数学模型,对其进行了误差分析,并提出了在线检测的实现方法和作用。     

点阵式测头成像视觉三坐标测量系统建模

在透视投影和坐标变换的基础上,建立测头成像视觉三坐标测量系统的数学模型;求解了共线、共面和空间三种点阵式测头构成的系统模型,以最简单的共线三点型点阵测头为例建立实测视觉坐标测量系统,实验结果证明系统模型的正确性。     

复杂曲面零件加工精度的原位检测误差补偿方法

为提高复杂曲面零件的数控机床原位检测精度,分析影响接触式检测系统精度的各项因素及其误差补偿方法。对检测系统的主要误差来源如机床几何误差、测头预行程误差和测头半径误差进行分析研究。在对数控机床的几何误差进行分析和建模的基础上,采用激光干涉仪进行三轴数控机床的单项误差测量和补偿;针对测头检测过程中存在的预行程误差,提出基于径向基函数(Radial basis function, RBF)的预行程误差预测方法,获得测头预行程误差分布图,并对检测系统进行实时预行程误差的补偿;提出改进的三角网格模型顶点法矢计算方法,有效进行三维测头的半径补偿。通过实例零件的加工精度原位检测试验及其与三坐标测量机CMM检验结果的比较,验证了原位检测方法的有效性。     

THEORETICAL ANALYSIS OF COORDINATES MEASUREMENT BY FLEXIBLE 3D MEASURING SYSTEM

The system mathematical model of flexible 3D measuring system is built by theoretical analysis,and the theoretical formula for measuring space point coordinate is also derived. Frog-jumping based coordinate transform method is put forward in order to solve measuring problem for large size parts. The frog-jumping method is discussed,and the coordinate transform mathematical model is method of the space point coordinate compared to original value,and an advanced method is provided. Form the space point coordinate transform formula can derive the calculation measuring method for measuring large size parts.     

面向飞机大部件的智能三坐标辅助测量技术研究

为实现飞机大部件型面的高精度、高效率和自动化三维测量,对测量的关键技术进行了研究,研制出一套面向飞机大部件的智能三坐标辅助测量系统。该系统以导航小车为平台,以夹持有靶标的直角三坐标伺服机构为载体,通过激光跟踪仪实时反馈靶标位置进行闭环控制实现误差补偿,采用离线编程对导航小车和直角三坐标伺服机构进行任务规划,在保证测量精度和测量范围的同时实现了产品的自动化测量。实验结果表明,该测量系统简单有效,适用范围广,具有较大推广价值。       

考虑装配图生成和修改的二维参数绘图系统

结合已有的零件图参数化技术和基于深度测试的装配图消隐技术,提出了一种对装配图进行参数化修改的新技术,论文详细讨论了零件图参数化模型和装配图修改模型的建立过程及特点。     

考虑装配图生成和修改的二维参数绘图系统

结合已有的零件图参数化技术和基于深度测试的装配图消隐技术，提出了一种对装配图进行参数化修改的新技术。详细讨论了零件图参数化模型和装配图修改模型的建立过程及特点。     

Real-time tension control in a multi-stand rolling system

The problem of real-time tension control in a metal-strip processing line is addressed. The tension in a metal strip changes due to not only the speed difference but also thickness changes at the ends of a span. The mathematical dynamic model which describes relationship between the tension change and the roll-speed change is improved to include the effect of the strip thickness change on tension variation. Through the computer simulation of this model. the parameter sensitivity analysis and the static and dynamic characteristic study are carried out. The tension variation in a metal strip turned out to be very sensitive to the thickness variation as well as to the speed difference at the ends of the metal strip. In the rolling process, the master speed drive is usually located at the last stand. The speeds of rollers in upstream stands are adjusted with respect to the speed of the last stand to compensate the speed change for the tension regulation. A new tension control strategy in a multi-stand rolling process is suggested. The tension transfer phenomena is used in the design of the suggested controller. The developed mathematical model is used to design a controller for the real-time control system. A set of requirements for the real-time tension control is suggested. Based on the requirements, a real-time software for the tension control in a multi-stand system is designed and real-time simulation was carried out by using the Vx Works real-time scheduler and the Force Target board. The cancellation mechanism of the roll gap control due to the tension interaction is clearly defined by using the mathematical model derived in this study. It is confirmed that the suggested control strategy needs less control efforts and shows better performance than those of the existing control method in a rolling process.     

过约束平面并联三维力/力矩传感器的研制

针对轴承的故障早期诊断和在线实时监测,提出了一种新型过约束平面并联三维力/力矩传感器。通过采用分支轴线均不过传感器中心的6条对称分布的测力分支,该传感器可同时测量轴承径向载荷和轴向力矩。根据静力学平衡方程,求解了其测量数学模型;基于传感器测量模型与性能指标分析了传感器性能,进而对其各结构参数进行优化设计。研制了传感器样机及其加载标定实验系统,开展了加载标定实验,得到了该传感器的测量精度。标定实验结果显示:传感器径向力测量精度为2.56%,力矩测量精度为0.92%,Ⅰ类误差为2.56%,最大Ⅱ类误差为2.29%。文中所做工作,为将该新型过约束平面并联三维力/力矩传感器应用于在线实时测量轴承径向载荷和轴向摩擦力矩奠定了基础。     

液力机械变速箱试验台计算机模型参数自适应控制系统

本文介绍了液力机械变速箱耐久性试验台计算机自动控制与数据采集系统及其主要性能;推证了J.I.Soliman提出的柴油机的数学模型,导出了这种数学模型的模型参数的数学表达式;建立了较高精度的液力变矩器工程实用数学模型。设计的具有模型参数自适应补偿的计算机控制系统能实时地适应试验台工况的变化,自动整定其模型参数,使其转速调节过程仍然具有较好的静、动态指标。现场实测结果表明研制的计算机控制系统是成功的。     

Fuzzy Controllers in the Adaptive Control System of a CNC Lathe

Traditional approaches to improving the technological system of CNC metal-cutting machines include increasing the rigidity, periodic maintenance and repair of its components, and operating at lower speeds. In practice, the most economical approach is stabilization of the inputs to the system. The development of adaptive control systems with stabilization of the cutting forces improves the precision and quality of machining in CNC metal-cutting machines, the productivity, and tool life. However, classical PID controllers are only effective in stabilizing the cutting forces in such systems if continuous real-time parameter adjustment is possible. That sharply increases the complexity of the controller. A new mathematical apparatus based on artificial intelligence (including fuzzy logic) permits the solution of adaptive control problems that previously could hardly even be formulated. The present work addresses the use of fuzzy logic in automatic stabilization of the cutting force for CNC lathes. Simulation of a fuzzy controller shows that this approach to automatic stabilization of the cutting force increases the machining efficiency on existing equipment with indeterminacy in the characteristics of the cutting system and the working environment.     

Integrating modeling mechanism for three-dimensional casting process model based on MBD

The objective of this research is to propose an integrating modeling mechanism for three-dimensional casting process model (TDCPM) based on model-based definition (MBD). Firstly, the structure of the three-dimensional casting process model is put forward, and the TDCPM is comprised of three components: (1) process geometry model, (2) process information, and (3) process dimension information, building the relationship between the three components and give the planning procedure. Secondly, research the construction process of the casting part, gating system, and risering system; provide data structure, analysis method, and rebuilding mechanism of process dimension information; and introduce the casting process parameter and process planning history mechanism for TDCPM. Finally, a casting process planning system prototype is developed based on the proposed modeling mechanism.     

微颗粒的三维空间跨尺度装配方法

针对微颗粒空间装配的问题,以外径为十几微米的微颗粒与外径为几百微米的柱腔装配为研究对象,开展微颗粒空间跨尺度装配方法研究。首先,针对微颗粒受到基底表面作用力影响不易被拾取与释放的问题,分析了微颗粒的受力情况,设计了真空吸附式微夹持器用于微颗粒的拾取与释放;然后,针对由于微颗粒与柱腔的尺寸跨度大,很难实现装配过程中二者空间位置实时监测的问题,设计了具有多维视觉监测功能的微装配机器人并且建立了多维视觉监测模型,实现微颗粒与柱腔装配过程的在线监测;最后,提出了基于多维视觉监测模型的微颗粒与柱腔空间半自动装配方法。实验结果证明了所提方法的有效性,并且实现了将外径为20μm的微颗粒放入外径为200μm的柱腔内的目标。该方法适用于微机电系统制造中微颗粒的三维空间装配。     

双目视觉测量系统结构参数设计及精度分析

为提高视觉测量系统的测量精度,针对双目视觉系统结构,采用三角法建立了双目视觉测量系统的结构参数模型,分析了双目视觉系统结构参数与空间被测点之间的关系特性,研究了各结构参数对测量精度误差分布的影响,根据仿真结果给出了小误差时的结构参数的最佳取值范围。     

具有三维力反馈的原子力显微镜纳米操作系统

在基于原子力显微镜的纳米操作过程中，由于缺乏实时反馈信息，造成纳米操作效率低下且灵活性差，同时探针因受力过大而损坏。为此，本文通过对探针受力-悬臂变形进行建模，并根据实时检测到的悬臂变形信号、新的参数获取与校准方法，从而获取探针所受的实时三维纳米力。将此三力经比例放大后送人力／触觉设备进行感知，操作者就可以实时调节施加在探针上力的大小及探针的运动轨迹，使得操作的效率及灵活性明显提高，且可以避免探针因受力过大而造成损坏。纳米刻画和多壁碳纳米管的操作实验验证了系统的有效性。