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管件带坡口相贯线数控切割建模与仿真研究

Study on Modeling and Simulation on Cutting Groove Intersections of Pipes

【作者】 董本志

【导师】 郭艳玲;

【作者基本信息】 东北林业大学 , 机械设计及理论, 2010, 博士

【摘要】 近年来,随着我国钢结构应用的日益广泛,具有带坡口相贯线一次切割成型能力的5轴联动以上数控切割机逐渐开始应用。由于加工轨迹编程等工艺环节非常复杂,此类设备均需配备专用的辅助软件。目前,虽然有极少数国内企业能够制造此类设备,但和国外相比还存在较大差距,数控切割设备配套软件技术水平的落后是一个重要制约因素。因此,本文针对实际工程应用中最为普遍的圆管、圆锥管和方管间相贯问题,展开了对自动编程、自动后处理、仿真校验和虚拟训练技术的研究工作。为使研究结果更具有普适性,本文基于一种功能全面的六轴龙门式数控切割机模型进行研究。通过对圆管、圆锥管和方管带坡口相贯线切割过程进行运动分解,确定了切割不同类型管件时所需的联动轴,建立了各联动轴间的运动速度数学约束模型。在此基础上,根据管件轮廓特点和相贯线切割轨迹的空间直线拟合需求,提出了一种便于计算机求解的相贯线计算方法。该方法首先为主管和支管建立各自的坐标系,并分别建立参数式方程;然后根据两者坐标系之间的位置关系建立支管坐标系到主管坐标系的坐标变换矩阵,利用坐标变换方法将支管参数方程映射到主管坐标系中以求解主管上的相贯线切割轨迹;最后再将求得的轨迹进行逆变换,从而得到支管上的相贯线轨迹。利用该方法,建立了方管与方管、方管与圆锥管、方管与圆管、圆锥管与圆锥管、圆管与圆锥管、圆管与圆管相贯时的相贯线数学模型。对管件切割误差的构成进行了详细分析,建立了误差补偿模型。针对其中的安装误差和轮廓误差补偿问题,提出一种利用双目机器视觉技术进行误差获取的方法,对误差获取装置的构成和工作原理进行了说明,给出了根据连续捕获的图像重建钢管三维轮廓的算法,通过调整图像采集间隔,可方便的实现根据加工需要动态调整误差补偿精度的目的。研究了数控相贯线切割机仿真模块的构成,根据功能分析将虚拟仿真模块划分为虚拟机床、虚拟执行器和虚拟切割效果分析器三个主要组成部分。提出了一种快速搭建平台无关的虚拟相贯线切割机床的方法;给出了利用正规文法和上下文无关文法描述数控代码语法规则,进而根据文法编写数控代码译码程序的具体过程;探讨了虚拟运动控制器的构成和工作机制,用以使仿真切割过程与实际切割过程更为贴近;建立了虚拟割炬和风线的位姿计算模型,给出了在设置割缝误差补偿功能时的虚拟割缝的计算方法和图形绘制算法。研究了在采用火焰切割工艺时,提高切割仿真过程真实感的方法,根据对实际割焰的化学分析,建立了割焰的仿真模型,给出了采用粒子系统实现割焰视觉特效的方法,并对燃渣飞溅效果的产生方法进行了初步探讨。上述研究工作构成了比较完整的用于开发多轴数控相贯线切割机专用配套软件的技术链条。对本文工作进行进一步的深入研究和完善,可以大幅缩小我国数控相贯线切割机和国外产品在软件技术方面的差距。

【Abstract】 In recent years, along with the increasingly application of steel struct,5-axis or more complex CNC cutting machine has been gradually used to cut intersecting curves and its groove one time. As cutting path programming and other processing technics very complex, all of such devices need to be equipped with special assistive softwares. At present, although a handful of domestic companies to manufacture such equipment, but compared with foreign there are still a wide gap. CNC cutting equipment behind the level of supporting software technology is an important constraint. Therefore, this paper to be directed against the most common practical application of the circular tube, conical tube and square tube’s intersection problem, to launch study on the automatic programming, automatic post-processing, simulation and virtual training technology validation.To make sure the research more universal, all study is based on a full-featured six-axis CNC cutting machine model.Through intersecting curve cutting process with groove conduct sports decomposition for circular tube, conical tube and square tube determine required linkage axis cutting different types of pipe, established mathematical constraints model about move speed between every, linkage axis.On this basis, according to the tube outlined characteristics and space linear fitting needs of intersecting curve’s cutting locus, Proposed a kind of calculate methed,convenient gets solution for computer This method first for the head tube and the branch tube establish their own coordinate system, and respectively established parametric equations; then according to the position relationship between the two coordinate systems, established coordinate transformation matrix from branch tube coordinates to main tube coordinates, using coordinate transformation method make branch tube parameter equation is mapped to head tube coordinate system for solve intersecting curve’s cutting locus of main tube. At last carry on inverse transformation for getting locus then obtain intersecting curve’s cutting locus of. branch tube using this method, established intersecting curve mathematical model of square tube and square tube, square tube and the conical tube, square tube and round tube, conical tube and the conical tube, conical tube and circle tube, circle tube and circle tube.A detailed analysis for pipe cutting error composition is carrid on, the error compensation model is established also. Contrary to the installation error and contour error’s compensatory problem, a method of obtaining error using of binocular machine vision technology is proposed, conducted illustrate for error acquisition devices composing and working principle are described, given arithmetic according to reconstructed three-dimensional outline of steel profile through capture continuous image, by adjusting the image acquisition interval, can be easily achieved popose for dynamically adjusted error compensate filter. Another study is concentrated on the structure of simulation module composition of CNC intersecting curve’s cutting machine. This module can be used to simulate the NC program and can be used to process a virtual operator training too. According to functional analysis, the virtual simulation module is divided into three major components include virtual machines, virtual actuator and the virtual analyzer of cutting course. Proposed a method about constructing platform-independent virtual intersecting curve’s cutting machine quickly. The concrete procedure include using formal grammar and context-free grammar rules to discrib CNC code grammar rule and using these rules to build NC code decoder is brought forward. Formation and operating mechanism of the virtual motion controller are discussed to make simulated cutting process more similar with actual cutting process. The calculation model of virtual cutting torch and cutting wind position are established and the method of increasing the realism of cutting process simulation when using flame cutting technology are studied. In these reserch, a simulation model is established accoding to the chemical analysis of the actual cutting flame. On this basis, the course of producing visual effects cutting flame using particle system is elaborated. Finally, the effects producing technology of burning slag splashing is study preliminary.The study constitutes a entire technology chain that can be used to develop specific supporting software of multi-axis CNC intersection cutting machine. Work on this further in-depth research and improvement can significantly reduce the gap between domestic CNC intersection cutting machine and similar foreign products in the software technology area.

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