基于虚拟现实的煤矿设备装配仿真系统研究

针对煤矿大型设备装配存在拆装繁琐和成本高的问题,以采煤机、液压支架、掘进机和提升机为研究对象,采用虚拟现实技术设计并实现了一套由虚拟装配子系统、场景仿真与漫游子系统组成的虚拟装配与仿真系统.利用Maya对大型设备建模,通过VS程序设计,在Unity中进行交互控制,实现了设备的虚拟装配与拆卸、采煤工作面的虚拟仿真漫游功能.系统有效地提高了训练效果,形象逼真地再现了煤矿井下生产过程,具有良好的沉浸性和交互性.测试表明:经该仿真系统训练与使用,有效提高了设备实际装配与拆卸能力,同时降低了成本,具有显著的实际应用效果.     

产品虚拟装配培训系统的研究

虚拟现实技术为产品的装配培训提供了一种高效、互动的途径.该文介绍了研究设计的产品虚拟装配培训系统的硬件组成、软件开发工具以及系统内核的总体结构,着重探讨了装配工艺路径有效性检查和路径合成两项关键技术,并提出了一种面片级的快速干涉检查算法.     

航空发动机教学实验系统的虚拟装配技术研究

航空发动机虚拟教学实验系统的建设是将VR(Virtual Reality)技术与实验相结合的一次综合性的实验探索与尝试.该系统是将虚拟装配及拆卸、模化实验、模型流场的动态显示及发动机试车等综合仿真实验系统,重点论述了教学实验系统开发中的虚拟装配技术,在对虚拟装配的研究现状分析和总结的基础上,对航空发动机虚拟装配的关键技术和虚拟装配系统的实现方法进行了分析和研究,包括基于数据手套的虚拟手操作、实时碰撞检测、装配路径和装配顺序规划等问题.最后还展示了利用航空发动机三维可视化虚拟装配系统完成虚拟装配操作的实例,并分析了虚拟装配系统与传统装配相比较的优势和特点.     

45 t岸边集装箱起重机可视化装配仿真

为缩短岸边集装箱起重机生产制造过程中的装配周期并降低成本,针对某45 t岸边集装箱起重机,基于面向装配设计的方法引入可视化虚拟装配技术,运用CATIA对其进行虚拟装配仿真分析,确定零部件装配层次关系,设计零件的部装、预拼装和总装等部分的整体装配流程.在CATIADMU平台建立基于仿真试拆卸的装配路径规划流程,并以运行小车滑轮组为例分析装配路径规划并进行装配干涉检查.该方法可以直观地显示出各零部件的可装配性,优化岸边集装箱起重机装配结构.     

拖拉机前驱动桥虚拟装配应用研究

在分析和总结了虚拟装配技术研究现状的基础上,阐述了其原理,实施步骤以及关键技术的应用,并以拖拉机前驱动桥为虚拟装配对象,在计算机虚拟装配环境(Division Mockup)中装配并进行相应的装配检验,介绍生成装配序列与装配路径,并制作成装配动画的步骤,形象地展现产品的装配全过程.在(Division Mockup)中...     

虚拟环境中产品装配过程回溯方法研究

在记录虚拟装配过程的基础上，提出基于任务时间的虚拟装配过程整体回溯与基于任务对象的虚拟装配过程局部回溯方法．虚拟装配过程整体回溯以装配任务时间为回溯准则，允许将装配场景中零部件的方位与装配关系回溯到曾经存在的装配历史状态，而虚拟装配过程局部回溯，是根据装配序列中零件间装配约束与几何干涉方面存在的相关性进行装配过程的选择性回溯．文中方法在虚拟设计与装配原型系统开发中得到实现．实践表明，装配过程回溯方法有效地提高了虚拟环境中产品装配设计的效率。     

采用边界拉伸的干涉检验方法与装配顺序规划

干涉检验及装配顺序规划为虚拟装配中的关键技术和重要研究内容。干涉检验的一般算法是用离散运动轨迹求得动态干涉,但其运动步长很难掌握。提出一种基于边界拉伸的干涉检验方法,将离散干涉检验转化为连续干涉检验,减少了运算量,提高了效率。并在此干涉检验算法基础上,进一步对装配顺序进行规划。实践表明,方法行之有效。     

基于语义的虚拟装配仿真模型研究及应用

针对虚拟装配中装配模型的信息完备性与虚拟仿真系统的交互效率之间的矛盾,提出一种轻量化的基于树-图分离结构的虚拟装配模型,该模型包括装配树模型和语义关系图模型。装配树模型以二叉树的形式表达虚拟产品的层次结构以及零部件间的装配顺序,语义关系图以二分图的形式表达零件之间的装配关系。将该模型应用于水轮机组虚拟装配仿真系统中,不仅满足了虚拟仿真过程对装配模型信息表达的要求,而且减少了系统存储负担,提高了交互效率。     

交互式拆卸引导装配路径规划方法研究

在分析研究虚拟装配中的装配路径生成办法的基础上,根据实际需要提出了以交互式拆卸引导的装配路径规划方法的装配路径规划优化算法.算法主要通过人机交互的方式,记录零部件在拆卸过程中不同状态下每一步关键点的位置姿态信息.根据装配过程是拆卸过程反演的原则,通过“拆卸引导”形成零部件的装配路径,经过多次人机交互调试最终实现装配的最优路径.该算法的目的是生成无碰撞、无干涉的优化装配路径,从而实现虚拟环境中零部件更快捷、有效地装配.     

工程结构虚拟装配引擎的动画设计实现

为了对工程结构的装配施工过程进行仿真,设计实现了虚拟装配引擎OpenWorld。本文论述了该引擎采用的实体层次结构建模和模型支持系统,提出了将场景分为世界场景和独立场景集合的渲染方式,并设计实现了一套可编辑的XML动画格式标签。利用该引擎设计完成的虚拟装配软件对工程设备的装配起到了成功的指导作用,减少了装配过程中的误操作。     

面向虚拟装配的AVI视频动画制作算法研究及应用

介绍了在虚拟环境下通过动画记录工具将产品零部件的装配顺序和装配路径等工艺结果形成装配过程动画的方法,以此建立可视化的装配工艺文档。给出了动画记录工具的具体算法及实现,可以将装配过程记录成AVI文件。并以自主开发的虚拟装配系统VAPP为例,对算法进行了验证。     

Assembly simulations in virtual environments with optimized haptic path and sequence

Virtual assembly and disassembly simulations can be accomplished in intuitive and effective ways using haptic information in virtual environments (VEs). Potential problems in a given assembly scheme can be predicted by a user who may be able to suggest an alternative scheme in the VE. This paper describes an intelligent virtual assembly system in which an optimal assembly algorithm is used to allow haptic interactions during virtual assembly operations. This algorithm provides optimal paths for haptic guidance as well as an assembly sequence of the parts to be assembled. The performance of the given assembly schemes was simulated using a virtual assembly system. Experimental results showed that the haptic-path sequence-guidance (HSG) mode gave the best performance improvement in terms of accumulated assembly time (28.33%) and travel distance (15.05%) compared to the unguided mode, while the sequence-guidance (SG) mode alone increased performance by 15.33% for assembly time and 11.36% for travel distance. The experimental results were analyzed by the sub-tasks of gripper selection, inter-part movement, and part assembly. For the HSG mode, the greatest contributor to the time and distance reductions was the optimized haptic path, while for the SG mode, the reduced numbers of gripper exchanges and orientation change made the greatest contributions to reducing the assembly time and the travel distance. As a result, the optimized haptic path, as well as sequence guidance, enhanced the working performance of virtual assembly tasks.     

汇编程序覆盖测试中虚拟插桩的实现

在对汇编语言源程序的测试工作中,由于其非结构化的设计思想以及众多的跳转指令,使得插桩非常困难。该文在汇编嵌入式软件程序流程图自动生成的研究基础上,提出了以PC值为基准条件的断点设置、检测机制以及虚拟插桩机制。并结合特定的测试用例在仿真测试平台上得以实现,最后通过实验检验了其正确性。     

VDVAS：一个集成的虚拟设计与虚拟装配系统

随着虚拟现实技术的逐渐成熟，研究者们已将其引入到工程领域，为实现虚拟设计与虚拟装配过程的集成，避免现有的虚拟装配系统中，虚拟环境与CAD系统间所必需进行的复杂的、无谓的数据传输，描述了一个基于多通道的、集成的虚拟设计与虚拟装配系统VDVAS。在该系统中，设计得可以通过直接三维操作和语音命令直观方便地建立机械零件及其装配模型，并通过交互拆装来得到零件的装配顺序和装配路径等信息，VDVAS的一个重要特征在于，可通过集成虚拟设计与虚拟装配过程，使设计者能在一个集成的虚拟环境中修改零件几何（假如在装配过程中发现零件存在设计缺陷的话）。     

Studies on visual scene process system of aircraft assembly

According to the aircraft assembly worksite scene process, the hierarchical data model based on PPR (product, process, resources) was got to achieve the conversion in various types of aircraft assembly process data model. At the same time, the lightweight technology and human–computer interactive scene control technology were researched to obtain the lightweight of three-dimensional (3D) model and site scene and the human–computer real-time interaction between people and virtual environment through the computer keyboard and mouse, respectively. And then, the visual assembly sequence planning algorithm based on the parallel binary-coded was suggested to complete the aircraft assembly sequence planning. On the basis of techniques mentioned above, we developed the assembly worksite scene process system, which can be integrated with PDM system. At last, an application case of aircraft nose assembly was given, and the result was proved to be effective.     

面向并行设计的装配顺序规划研究

该文根据先进制造发展的特点,结合现代设计理论提出了适合敏捷制造的面向并行设计的装配顺序规划系统结构.针对在自动装配顺序规划过程中没有实际接触零件之间相互干涉这一难点问题,应用了虚接触原理,并给出了相应的虚接触生成规则.为了使设计人员和用户更有效地获得装配信息,提出了信息反馈规则.文中结合例子讨论了虚接触和信息反馈在生成可行装配顺序推理过程中的应用,证明了其可行性和有效性.最后讨论了在虚拟现实环境中进行装配仿真的优势和意义.     

大豆形态生长系统的组件化设计方法

针对以往作物形态生长系统对器官分类管理不强、代码可重用性差等问题,本文运用可视化和组件化的计算机软件编程理论,设计基于组件技术的作物形态生长系统,体现组件技术灵活、易于管理、代码重用等的特点,可以为模拟系统提供功能扩展接口,为模拟大豆群体形态奠定基础,对虚拟作物的可视化研究具有重要意义。     

A knowledge intensive multi-agent framework for cooperative/collaborative design modeling and decision support of assemblies

Multi-agent modeling has emerged as a promising discipline for dealing with decision making process in distributed information system applications. One of such applications is the modeling of distributed design or manufacturing processes which can link up various designs or manufacturing processes to form a virtual consortium on a global basis. This paper proposes a novel knowledge intensive multi-agent cooperative/collaborative framework for concurrent intelligent design and assembly planning, which integrates product design, design for assembly, assembly planning, assembly system design, and assembly simulation subjected to econo-technical evaluations. An AI protocol based method is proposed to facilitate the integration of intelligent agents for assembly design, planning, evaluation and simulation process. A unified class of knowledge intensive Petri nets is defined using the O-O knowledge-based Petri net approach and used as an AI protocol for handling both the integration and the negotiation problems among multi-agents. The detailed cooperative/collaborative mechanism and algorithms are given based on the knowledge objects cooperation formalisms. As such, the assembly-oriented design system can easily be implemented under the multi-agent-based knowledge-intensive Petri net framework with concurrent integration of multiple cooperative knowledge sources and software. Thus, product design and assembly planning can be carried out simultaneously and intelligently in an entirely computer-aided concurrent design and assembly planning system.     

Methods and Algorithms for Constraint-based Virtual Assembly

Constraint-based simulation is a fundamental concept used for assembly in a virtual environment. The constraints (axial, planer, etc.) are extracted from the assembly models in the CAD system and are simulated during the virtual assembly operation to represent the real world operations. In this paper, we present the analysis of combinations and order of application of axial and planar constraints used in assembly. Methods and algorithms for checking and applying the constraints in the assembly operation are provided. An object-oriented model for managing these constraints in the assembly operation is discussed.