一种非圆齿轮虚拟插齿加工建模及切屑方法研究

非圆齿轮因其节曲线为非圆形,加工过程复杂,加工仿真困难。针对一种非圆齿轮的加工,实现了从毛坯到成品的虚拟插齿过程仿真,即按照事先编制的G代码(即数控程序),驱动虚拟插床有序去除虚拟毛坯材料。通过对毛坯模型进行离散化,在切割过程中不断从场景中移除切屑材料节点实现加工仿真;通过树状场景图结构搭建虚拟加工环境;数控插齿加工过程复合运动的协调运作,实现了基于G代码的加工过程运动仿真。采用Visual Studio 2008作为开发平台,结合OSG(open scene graph)图形库,再现了加工中工件的成型过程,为产品加工过程提供了有益的参考。     

三维虚拟加工环境及其关键技术的研究

在分析虚拟制造特点的基础上,提出了三维可视化虚拟加工环境的系统结构,介绍了支持三维建模仿真的组件设计、基于装配模型的三维实体建模方法、NC代码解析器的设计方案以及基于毛坯表面三角片离散化的加工过程仿真算法,并开发了虚拟加工环境原型系统,该系统能够实时地反映零件虚拟原型的加工成形过程仿真,并进行可加工性分析。     

基于虚拟制造的三维数控仿真系统开发

本文评述了虚拟制造技术和三维数控仿真的含义和发展,结合虚拟制造技术对数控仿真系统进行了研究,提出了三维可视化虚拟加工环境的系统结构,通过对设计过程中相关技术要点的探讨,运用OpenGL、VB和VC 等软件,开发出基于虚拟制造的三维数控仿真系统。     

基于动态局部更新体素模型的虚拟加工仿真算法研究

为提高虚拟加工仿真算法的仿真速度和精度,提出一种新的基于动态局部更新体素模型的虚拟加工仿真算法.该算法利用体素节点间的邻接关系,实现虚拟加工仿真的动态局部更新.算法在初始化阶段建立虚拟毛坯的八叉树结构体素模型,并建立任意体素6-邻接关系遍历算法.在虚拟加工几何仿真阶段,利用刀具和毛坯相对运动的时空一致性,从毛坯上一帧已...     

虚拟加工中心加工过程算法研究

在虚拟加工环境的建造过程中，关键技术是三维实体的数据结构和加工仿真的逐步成型算法。该文重点研究了毛坯的数据结构特点，四边形离散化方法和毛坯文件的存储格式等，并且分析了三坐标加工中心的加工特点，同时还给出了虚拟加工过程中毛坯被加工成工件的逐步成型算法。该算法在虚拟加工环境中得到了成功应用，文中给出了该算法在三坐标加工中心的验证实例。     

虚拟手术中软组织切割模型研究进展*

虚拟手术仿真训练系统是虚拟现实的重要应用,能够克服真实传统手术中资源少、训练不方便和可重复操作性差等问题。软组织切割是虚拟手术仿真训练系统中的重要组成部分,也是手术中最常见的操作。软组织切割模型建立的质量如何,直接决定了虚拟手术仿真的精度度和仿真度。为更好地对软组织切割模型进行深入探索,分析了虚拟手术仿真中软组织切割的研究难点。针对当前十四种有代表性的切割模型进行了研究,在此基础上对这些模型的优缺点进行了比较,并对软组织切割模型的发展趋势进行了展望。     

嵌入式数控系统中3D加工仿真模块的实现

基于Cortex-A8和Android软硬件嵌入式数控平台,提出一种集成到中低端数控车床加工系统的仿真模块设计方法。在三角网格离散法建模的基础上,提出利用顶点平移算法计算三角片的顶点坐标值,大大减少复杂的三角函数计算量,并且基于强大的嵌入式三维图形Open GL-ES2.0接口绘制毛坯;基于NC代码特征解释译码,有效提取出刀具驱动数据信息;在刀具切削过程中,对扩展DDA圆弧插补算法进行改进,提高了切削精度。动态仿真测试表明:基于改进的算法进行加工仿真,3D效果逼真,插补点径向误差减小30%左右,加工仿真精度高。     

机械零件加工工艺的计算机仿真系统研究

本文结合计算机辅助工艺设计和图形学技术,介绍了一个零件加工工艺的图形仿真系统,用工艺代码作为输入,与工艺的描述相对应,根据切削参数检验工艺的合理性,动态显示各加工阶段毛坯的形状变化,显示刀具运动轨迹,判断是否存在碰撞和过切现象,并提供了多个切削函数。     

虚拟加工中工件毛坯模型的建立

为解决虚拟加工中工件毛坯模型的识别问题,提出对规则形状工件毛坯采用OpenGL建模、对复杂形状工件毛坯采用美国初始图形交换规范（Initial Graphics Exchange Specification,IGES）文件进行模型数据转换的方法.该方法利用CAD软件为工件毛坯进行三维造型,生成IGES文件,然后在虚拟加工环境下读取IGES文件并生成工件毛坯模型,从而实现工件毛坯模型在新环境中的建立.经过建立具体的工件毛坯模型,验证相关理论的正确性,为在虚拟加工环境下工件毛坯模型的建立提供可行的依据.     

制造系统虚拟仿真的设计和实现

介绍了制造系统虚拟仿真的设计和实现问题。给出了虚拟仿真的体系结构和设计思想 ,并分别论述了设计制造系统虚拟仿真的几个主要问题及其实现细节。包括仿真模型和使用的仿真算法 ,基于OpenGL的动态几何建模 ,定义和描述虚拟设备的加工活动 ,场景组织、声音的合成、及系统与用户的交互 ,并给出了一个基于PC的仿真实例。     

虚拟数控铣削加工系统的研究与开发

在研究虚拟制造技术、数控加工技术的基础上，采用VC 程序语言开发了一套用于数控机床实验教学的虚拟数控铣削加工系统。该系统具有与真实数控铣床类似的虚拟控制面板和床身，能够实现加工过程的三维仿真和加工过程的干涉检查；该系统可以检查NC程序代码中的语法错误，从而减少了用试切法检查所带来的资源浪费和设备损耗，提高了数控设备的利用率。     

Construction of a computer-simulated mixed reality environment for virtual factory layout planning

To survive the cut-throat competition in the manufacturing industry, many companies have introduced digital manufacturing technology. Digital manufacturing technology not only shortens the product development cycle times but also improves the precision of engineering simulation. However, building the virtual objects needed for a digital manufacturing environment requires skilled human resources; it is also costly and time-consuming. A high precision environment with the similar resources is also needed for a high precision simulation. In this paper, we propose a method of constructing a mixed reality-based digital manufacturing environment. The method integrates real objects, such as real images, with the virtual objects of a virtual manufacturing system. This type of integration minimizes the cost of implementing virtual objects and enhances the user's sense of reality. We studied several methods and derived a general framework for the system. Finally, we developed our idea into a virtual factory layout planning system. To assign the pose and position of real objects in virtual space, we applied a circle-based tracking method which uses a safety sign instead of the planar-square-shaped marker generally used for registration. Furthermore, we developed the framework to encapsulate simulation data from legacy data and process data for visualization based on mixed reality.     

A Survey of Physically Based Simulation of Cuts in Deformable Bodies

Virtual cutting of deformable bodies has been an important and active research topic in physically based modelling and simulation for more than a decade. A particular challenge in virtual cutting is the robust and efficient incorporation of cuts into an accurate computational model that is used for the simulation of the deformable body. This report presents a coherent summary of the state of the art in virtual cutting of deformable bodies, focusing on the distinct geometrical and topological representations of the deformable body, as well as the specific numerical discretizations of the governing equations of motion. In particular, we discuss virtual cutting based on tetrahedral, hexahedral and polyhedral meshes, in combination with standard, polyhedral, composite and extended finite element discretizations. A separate section is devoted to meshfree methods. Furthermore, we discuss cutting‐related research problems such as collision detection and haptic rendering in the context of interactive cutting scenarios. The report is complemented with an application study to assess the performance of virtual cutting simulators.     

虚拟数控铣床加工过程仿真研究*

基于虚拟柔性制造系统,着重从几何仿真的角度对数控铣床模型的建造和加工过程仿真的有关问题进行了研究。在建模过程中重点研究了数控铣床模型的简化、基于OpenGL和Pro/E的格式转换,并在虚拟仿真环境中,根据铣床的构造特点,建立了铣床的虚拟模型;在加工仿真过程中,针对铣床加工过程,对数控铣床的多轴联动机制进行了约束和定义,并对数控代码进行了分解,采用数字脉冲的驱动方式,成功模拟了加工过程的直线和圆弧等常用插补,形成工件轮廓。     

A sales agent for part manufacturers: VMSA

The sales activity of most parts manufacturing companies is based on orders of buyers. The process of promotion, receipt and selection of orders of the parts manufacturers is closely coupled with the load status of the production lines. On deciding whether to accept an order or not, as well as negotiating with buyers, sales persons need information such as load and schedule of production lines, and manufacturability of the order. Manufacturability analysis, process planning, and scheduling are therefore key features in developing an agent of sales activity for the parts manufacturing business. In this paper, an intelligent agent, a virtual manufacturing-based sales agent (VMSA) with multi-agent architecture is proposed to support the sales activity for the parts manufacturers in the Internet environment. A VMSA has an integrated architecture of agent and virtual manufacturing. The prototype of VMSA has been developed for a machine parts manufacturing company that has lathe machines, drilling machines, cutting machines, and milling machines.     

A simulation analysis of the effectiveness of drum-buffer-rope scheduling in furniture manufacturing

Simulation has proven to be an important computer tool in analyziing new manufacturing approaches. In this paper we use simulation models to compare a new approach to manufacturing with current practices. The new approach is referred to as the Drum-Buffer-Rope (DBR) method of synchronous manufacturing. We discuss the DBR approach and demonstrate the application of DBR in a furniture manufacturing case example. Simulation models are used to compare the DBR approach with the typical system of production control referred to as a cutting approach. The simulation analysis indicates considerable savings in makespan are possible when DBR is used in place of the cutting approach.     

A multi-regional computation scheme in an AR-assisted in situ CNC simulation environment

Computer numerical control (CNC) simulation systems based on 3D graphics have been well researched and developed for NC tool path verification and optimization. Although widely used in the manufacturing industries, these CNC simulation systems are usually software-centric rather than machine tool-centric. The user has to adjust himself from the 3D graphic environment to the real machining environment. Augmented reality (AR) is a technology that supplements a real world with virtual information, where virtual information is augmented on to real objects. This paper builds on previous works of integrating the AR technology with a CNC machining environment using tracking and registration methodologies, with an emphasis on in situ simulation. Specifically configured for a 3-axis CNC machine, a multi-regional computation scheme is proposed to render a cutting simulation between a real cutter and a virtual workpiece, which can be conducted in situ to provide the machinist with a familiar and comprehensive environment. A hybrid tracking method and an NC code-adaptive cutter registration method are proposed and validated with experimental results. The experiments conducted show that this in situ simulation system can enhance the operator’s understanding and inspection of the machining process as the simulations are performed on real machines. The potential application of the proposed system is in training and machining simulation before performing actual machining operations.     

A simulation model for the fabrication of components made from multiphase perfect materials

A component, which has an optimized combination of different materials (including homogeneous materials and different types of heterogeneous materials) in its different portions for a specific application, is considered as the component made of a multiphase perfect material. To manufacture such components, a hybrid layered manufacturing technology was proposed. Since it would be risky and very expensive to make such a physical machine without further study and optimization, manufacturing simulation is adopted to do further research so as to provide the reliable foundation for future practical manufacturing. This paper describes its virtual manufacturing technologies and modeling of the component virtually manufactured. Such a model can be used to evaluate the errors of the virtual manufacturing. Finally, an example of simulating manufacturing process and generating the model of the component virtually manufactured is introduced in more detail.