【作者】 崔岗卫；

【导师】 王瑜；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2008， 硕士

【摘要】 基于虚拟现实的虚拟装配技术为产品的装配问题提供了低成本的快速手段,而公差信息又是CAD/CAM信息集成中的关键技术,如何将二者有机集成是一个崭新课题。本文在分析总结国内外最新理论成果的基础上,为虚拟装配系统建立了一个公差产品模型,与一般的虚拟装配模型相比提高了模型的拟实性,进一步增强了虚拟装配的工程实用性。本文建立了基于虚拟现实的公差产品层次模型,基本数据采用数据库进行存储与管理,并开发了模型转换接口软件,基本数据可以自动提取,不需要用户的干预。实现了虚拟现实中零件几何模型的构建方法,以及装配信息、尺寸信息和公差信息的提取方法。开发了基于虚拟现实的公差产品建模系统,并结合实例探讨了公差信息的应用。机械零件的加工误差具有一定的随机性,按照不同的加工条件满足不同的分布规律。本文改进了特定分布随机数的生成方法,并将其应用于机械零件加工误差的随机生成,最后通过实验对该方法进行了验证。该方法适用性广,运算效率较高,适于任意分布且概率密度函数已知的加工误差的随机生成。配合特征矩阵可以用来表示装配约束,本文完善了这一方法,使得配合特征矩阵可以表示沿任意轴线的约束。分析了Pro/Engineer中常用的几种装配约束,并给出了其配合特征矩阵。详细分析了装配约束的获取与加载方法,同时重新定义了鼠标传感器和空间球传感器的刷新函数,从而完成了基于虚拟现实的装配过程的控制与仿真。更多还原

【Abstract】 Virtual assembly based on the virtual reality gives a low-cost and rapid prototyping method for products’assembly, and tolerances has become a key technique of information integration in CAD/CAM, it will be a new task that how to integrate tolerances into virtual assembly. On the basis of summarizing current research situations and developments both of abroad and at home, this thesis constructes a toleranced product model for virtual assembly, that is a more similar model to the product, so virtual assembly is more available.A toleranced product model based on the virtual reality is constructed for the virtual assembly, and the essential data is saved and managed in database. Model transform interface software is developed, that is a special software by which users can get the essential data without any users’acting. The geometric model of products is constructed in the virtual reality, and the method of getting assembly information, dimensions and tolerances is proposed. A toleranced product modeling system based on the virtual reality is developed, the using of tolerances is discussed by an example.Processing errors of machining part are random that obey different distributions according to the different manufacturing condition. The producing method of the random that distributes in a special law is improved on and applied for the random producing of the processing error. Then it is validated by experiments. This method can be applicable for many cases that the probability density function can be given, and this method is very efficient.This thesis make the mating feature matrix that can express constarints in the assembly product perfect, then constraints about an arbitrary vector can be expressed. The mating feature matrixs of some constraints in Pro/Engineer are discussed, and the method of getting and loading constraints are studied. The update functions of mouse and spaceball sensor are overwritten. The controlling and simulation of assembly process based on the virtual reality is finished.更多还原