【作者】 李鹏；

【导师】 王太勇；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2004， 硕士

【摘要】 切削过程仿真属于以制造为中心的虚拟制造中的一部分,借助于虚拟现实技术和仿真技术,模拟实际的切削加工过程,对数控加工程序的正确性进行检验,以减少或替代现场试切这一环节。本文在分析和研究现有研究成果的基础上,针对立式铣削加工中心的特点,主要对以下几个方面进行了深入的研究:1、采用层次化建模的方式,将加工中心分解成部件、零件和基本体素,组成建立了机床的三级装配树,建立了立式铣削加工中心的几何模型。在几何模型的基础上,运用矩阵运算的知识,建立了立式铣削加工中心的运动模型。在几何模型的搭建中,提出了自动换刀装置(ATC)的几何结构模型。2、在分析数控加工代码的特点和代码编译器的原理的基础上,设计了本系统的代码编译器,其中包括词法、语法分析模块以及数据处理模块。本代码编译器的设计采用数控系统中的真实插补算法进行加工离散点的计算,取代了以往仿真系统中的基于小时间片的离散计算方法。3、刀具数据库的有效管理方法。在现有立铣刀螺旋线模型理论的基础上,利用边界表示方法和OpenGL技术,构建了具有真实感的立铣刀实体模型。在分析刀具特点的基础上,利用ODBC数据库知识,实现了对刀具的管理功能,能够完成刀具的查找、编辑、添加、删除。4、采用基于小长方体的Z向离散方法建立零件模型和刀具仿真模型,通过零件和刀具在Z轴方向上的一维布尔运算来实现工件的切削,在加工过程中可以对工件进行多角度地观察,并且实现了刀具与工件互动的真实性仿真。同时,提出了自动换刀运动的简单动画表示方法。更多还原

【Abstract】 Cutting simulation is a part of virtual manufacturing, which simulates actuallycutting process by means of Virtual Reality and Simulation Technology. It can verifythe Numerical Control(NC) machine programs in order to reduce or replace the testprocess. In this paper, based on the analyses and investigation of current achievementsof vertical milling center, further research has been done in the following aspects.1.Disassemble machining center into parts, accessory and components byhierarchical modeling function. These three parts compose the three levels assemblingtree of the machine tools, and in this way, the geometry modeling of vertical millingcenter is founded. The movement modeling is founded by matrix operation based onits geometry modeling. The geometry structure modeling of ATC is put forward in theprocess of building the geometry modeling.2. This system code compiler, based on analyzing the character of NC code andthe theory of code compiler, is designed. This compiler includes analysis module ofaccidence, expression and data processing module. This compiler adopts realinterpolation arithmetic of NC system, replacing the disperse calculation methodbased on small time slice anciently.3. Available management of tool data-base. The solid model of end milling cutterwith third dimension is founded by B-rep molder method and OpenGL technology.This cutter model is based on existing theory of helix model. The management ofcutter, based on analyzing the character of cutter, is realized using ODBC data-baseknowledge. This module can accomplish the lookup, editing, adding and deleting.4. The part model and cutter simulation model, which is based on Z-orientatedsmall-cuboid dispersing method, is founded. The cutting process is realized throughthe one-dimensional bool operation which happens on the Z-orientated between thepart and cutter. In the cutting process, the multi-angle observation to part andauthentic simulation of the movement between cutter and part can be realized. At thesame time, the simple cartoon expression method of the movement of changing cutterautomatically is put forward.更多还原