Internet环境下面向中小型制造企业的三维虚拟设计方法

在分析虚拟现实系统的基础上,针对现有的Internet网络环境和我国中小型制造企业的实际情况,研究采用VRML和Java构建非沉浸式虚拟设计环境的实施方案,讨论基于虚拟原型的产品开发技术。以减速箱为研究对象构建的三维虚拟设计系统,验证这一方法表明,其是经济、实用的可行方法。     

基于VRML-JAVA的机器人运动仿真研究

随着微机性能的提高 ,虚拟现实仿真已能在微机上进行。本文对运用VRML JAVA技术在微机上进行机器人运动仿真进行了研究 ,提出了运用CAD软件造型来构造虚拟环境 ,然后用JAVA EAI接口控制虚拟机器人运动的方法 ,在此基础上对S70 0工业机器人进行了建模和运动仿真。结果表明在微机上实现一个跨平台、网络化的仿真平台是完全可行的 ,这样的系统将可应用于机器人离线规划和编程及可视化教学等领域。     

The application of virtual reality to tasks in manufacturing and assembly engineering

Virtual Reality is a developing technology for which a range of applications are heing explored by different international research groups. This paper describes recent research in the application of Virtual Reality to two important manufacturing and assembly tasks which have a direct influence on the speed of introduction of new products. The tasks are the production of planning documentation for assembled products and the design and planning of the cable harnesses which form part of all electro-mechanical assemblies. The research completed so far demonstrates the potential of Virtual Reality, even at its current stage of technological development, to make a significant contribution in both these cases.     

A systematic method of adaptive joint design considering different assembly sequence in sheet metal product

In sheet metal assembly, not only the component variations and tool errors, but also the component structure (joint type) and assembly process (assembly sequence) affect the final dimensional quality. In this paper, a systematic method for adaptive joint design considering different assembly sequence is proposed to meet the in-process dimensional adjustability of KCs (key characteristics). First, the adaptive characteristic of the sheet metal joint is depicted. Then, the mathematical model in order for concurrently optimizing both joint type and different assembly sequence is presented. How to evaluate the combination of joint type and assembly sequence is carried out according to two conditions: (1) for single KC, and (2) for multiple KCs. The KC confliction is considered to ensure the important KCs. Genetic algorithm is used to resolve the optimization of joint design. An example is chosen to demonstrate our method finally, and various joint designs are acquired according to different assembly sequences by this means. The proposed methods make it possible for us to improve the dimensional quality of product in the design stage.     

基于Web协同虚拟装配规划的实现

协同虚拟装配是借助于网络对产品进行数字化预装配 ,它是敏捷化设计与制造的基础。本文探讨了虚拟装配的协同机制 ,分析了产品设计过程中相关成员的需求并给出了客户端配置 ,探讨了系统开发工具的特性 ,建立了应用 VRML格式作为数据载体、基于 Web的虚拟装配框架体系。虚拟装配设计模块包括装配路径规划和干涉检查 ,文中分别给出了相应的算法     

产品装配设计中的生产模式技术与应用

计算机集成制造系统CIMS和并行工程CE技术的发展和应用,对装配设计提出更高的要求.实现产品设计与产品装配规划信息集成是实现产品计算机辅助自动装配的重要基础.在介绍课题研究的背景及意义的基础上,分析国内外装配设计及规划研究中常见的几项装配生产模式技术[1].     

基于Autodesk Inventor的三维参数化设计方法

应用三维Autodesk Inventor软件,以机械振动装置中板簧组件为例,介绍了零件的造型建模过程、零件的虚拟动画装配及判断虚拟装配中各零件之间是否相互干涉,从而对干涉的零件进行修改和结构调整的设计过程.体现了Autodesk Inventor软件在三维参数化设计中的强大功能及现代设计的优越性.     

基于Unity3D的减速器设计及展示系统研究

减速器作为机械传动的主要部件,其设计与制造过程一直是研究的热点。借助虚拟现实技术开发了减速器设计及展示系统,利用Unity3D引擎进行系统整体功能开发,实现了虚拟现实系统与三维建模软件间的数据传递和自动更新,基于PiXYZ软件优化了虚拟减速器的模型网格,并提出了虚拟减速器模型的干涉检查方法,阐述了基于虚拟现实的三维标注实现流程,提出了一种现实环境与虚拟环境叠加的增强现实展示方法。实践证明,融入虚拟现实技术的设计系统可大大缩减设计周期,具有很强的应用性和推广性。     

Constrained behavior manipulation for interactive assembly in a virtual environment

Interactive assembly based on virtual reality offers users an opportunity to interact with a virtual prototyping rather than a physical one and to validate assembly performance of products in a realistic way. Such evaluations could be available very early in the product development process ahead of any physical prototyping. The reduction or elimination of physical prototyping needed for assembly performance validation can substantially shorten the product development cycle and reduce development cost. Although virtual reality technology provides users an intuitive and immersive 3D interactive interface, it tends to be inaccurate because humans have difficulty in performing precise positioning tasks. Therefore, it is necessary to implement effective motion manipulation for assembly operations so that users can perform precise positioning efficiently in virtual assembly systems. This paper presents a constrained behavior management approach that realizes assembly relationship recognition, constraint solution and constrained motion for interactive assembly in a virtual environment. A constrained behavior manager (CBM) has been developed and applied in virtual assembly systems. Test cases confirm that constrained behavior manipulation proposed in this paper not only increases the efficiency of assembly relationship recognition, but also facilitates assembly interaction in a virtual environment.     

A systematic approach for green design in modular product development

In response to the changing market trend of having large varieties within a small production, green design and modular design have assumed significant roles in the product development process. This research applied quality function deployment (QFD) to achieve the goal of analyzing customers' needs. It also applied design structure matrix (DSM) based on the modular concept to group different design parts together to obtain optimized module efficiency. A balance between product development and ecological (ECO) friendliness can be achieved in advance if green QFD (GQFD) and DSM were introduced during the early design and manufacturing stages. Furthermore, using the result of GQFD, we proposed the analysis of DSM to find the result of coupled tasks. A pairwise comparative algorithm and loop analysis algorithm in DSM were utilized to decrease the number of module groups and find the most suitable clustering approach for further green design consideration. In this research, an electronic translator was used as a case study for the integration of green design with modularity. The main goal of this paper is to sort the importance weight values for green consideration by QFD during product development. These results can then be applied to finish modular grouping by DSM for subsequent green assembly and disassembly considerations of the products.     

A web-based 3D virtual technologies for developing product information framework

Information technologies and the web are challenging, and changing theway industry works. It is believed that web-based 3D interface can be applied to strengthen the interactive visualization and manipulation of products. In this research, a web-based 3D virtual technologies for developing product information framework is applied in automotive electric system. It is very convenient to share with different partners (e.g., co-designers, manufacturers, customers, etc.) via the web for viewing the aesthetic functions, and verifying its related design functions. The overall procedures are listed: First, build CAD models of automotive electric system (including assemble parts and their components) through CAD system, then store them in a relational database. Second, transforming the CAD models users click into virtual reality modeling language (VRML) objects, it can be visualized graphically and animated interactively using a web browser with a VRML plug-in. Finally, operate the VRML objects by Java Language for the different purposes. Due to the technologies that are applied, many interactive modes are generated in cyberspace. Displaying the exploding process of 3D assemble part on the browser, assigning any component of assemble part through the mouse chick directly to display design details, e.g., dimensions, tolerances, datum planes, material, other references, etc. by retrieving the corresponding data from database, and building 2D projected views automatically follow the 3D viewpoint that users assign.     

大型商用航空发动机科研装配线三维虚拟设计

为解决航空发动机科研装配线二维工艺布置设计存在的局限性,首先通过对大型商用航空发动机科研装配线的实体工艺要素三维建模,基于虚拟现实Unity3D开发平台,对已有二维工艺布置方案进行三维虚拟设计,实现了工艺要素的补充、细化和优化. 然后对新型的总装工艺过程进行了运动学仿真,并开发了人机交互的实时动态漫游程序. 研究成果为后期车间改造、工艺布置调整提供了预演和模拟分析平台,为企业的人员培训和宣传展示提供了重要素材,也为相关的制造厂房或制造单元设计提供了技术参考和借鉴.     

基于PDM协同设计任务建模与调度方法研究

从产品数据管理系统中协同设计过程任务建模的角度出发,提出基于产品结构分解的协同设计过程人员-任务分配模型,建立任务结构的约束映射和基于可扩展着色Petri网的任务过程建模方法,实现Multi-agent协同设计过程任务调度集成框架,最后进行了系统实现.     

基于虚拟现实面向用户的家具远程三维实时定制系统研究

针对目前主要基于文本和二维图形的网络化定制系统，为消除单纯文字描述的定制需求可能产生的误解，提出了基于虚拟现实和面向用户的家具远程三维实时定制系统方案，并对系统结构、三维模型的建立与优化、网络传输能力、系统集成等关键问题进行了研究。该系统利用VRML、Java和EAI等开放的技术与标准，采用浏览器／服务器／数据库三层网络结构，有助于提高远程定制系统的定制准确率和定制产品的客户满意度，进而提高企业的竞争力。     

并行工程中面向装配的设计

对计算机辅助装配序列规划作了分析 ,提出了产品可装配性评价的层次分析方法 ,分别从零件层和装配层对可装配性作了分析 ,在此基础上实现了面向装配的设计和计算机辅助装配序列规划集成。     

小生境遗传算法在混流装配线排序中的应用

在总结混流装配线排序问题的基础上,根据汽车制造业的实际情况建立一种新的汽车装配线排序模型.根据装配车型的关键件不同,引入车型相似度的概念,并将小生境遗传算法用于以最大化相似度总和为目标的混流装配线优化排序问题,同时将简单遗传算法和小生境遗传算法性能进行比较.最后通过在某汽车制造厂中的应用,验证小生境遗传算法在解决混流装配线生产排序问题中的有效性.     

A systematic approach for the sequence controller design in manufacturing systems

This paper presents a systematic approach for the design and implementation of the sequence controller in manufacturing systems. By employing the IDEF0, we construct the simplified Petri net controller (SPNC) through the material flow diagram and the information flow diagram. Then, the ladder logic diagram (LLD) can be transformed from the SPNC through the token passing logic (TPL). The proposed approach, including the IDEF0, SPNC, and TPL tools, leads to the standard IEC1131-3 LLD for PLC implementation. Finally, an application of a stamping process is provided to illustrate the design procedure of the developed approach .     

柔性装配制造系统中生产优化的Petri网方法

本文在基本Ｐｅｔｒｉ网的基础上,给出了一种进行周期性生产的柔性装配制造系统的模型;同时,针对该系统,给出了一个求稳定需求下最佳生产指量的启发式调度方法。     

三维零件的半智能化工序图生成系统

介绍了一种三维零件的半智能化工序图生成方法。通过采用中介信息元作为形位公差、表面粗糙度、加工基准及定位基准等非几何信息描述的载体，实现CAD与CAPP系统之间的信息共享；以零件的设计尺寸为起点，以CAPP系统中推理的零件加工工序表作为指导，通过逆向推理的方法获得中间各道工序的零件尺寸及相应中介信息元的信息；利用SolidWorks二次开发，实现根据三维几何模型生成二维图形及尺寸和公差的标注。最后给出系统的整体流程图。     

空间相机焦平面CCD交错拼接重叠像元数计算

针对大视场空间相机焦平面采用的多片CCD交错拼接,提出了一种适用于多种姿态模式的重叠像元数解析计算方法,以保证空间相机成像视场中不出现漏缝。分析了CCD交错拼接的成像特性和产生漏缝的原因;基于空间坐标系变换和中心投影共线方程建立了重叠像元数计算模型,对像点、相机摄像中心、地面景物点建立动态数学关系,通过追踪像点在像面上的运动轨迹计算了拼接缝像元重叠情况。结合实际工程样例,计算和分析了空间相机机动角度、星下点纬度、视场位置等因素对重叠像元数的影响,并将各工况下计算的最多漏像元数作为最终拼接量。结果表明:重叠像元数理论误差小于1pixel;对比侧摆,俯仰成像时所需拼接像元数更多;该计算模型可扩展应用于其他类型空间相机在任何姿态模式下的重叠像元数计算。