虚拟装配中的产品公差分析及优化分配研究

发布时间：2018-03-08 02:23

本文选题：计算机辅助公差设计　切入点：公差分析　出处：《杭州电子科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：产品的公差属性是产品加工和装配精度的直接体现,其不仅直接影响产品的性能水平,也很大程度上决定了加工制造工艺以及成本。因此,在产品的设计阶段就进行合理的公差设计,对于提高产品的可装配性、保障产品的质量水平、降低产品制造成本等方面具有重要的现实意义。计算机辅助公差设计(CAT)作为实现计算机辅助设计(CAD)和计算机辅助制造(CAM)集成的关键技术之一,其发展却相对滞后,对于CAT技术的研究工作仍然是国内外学者和企业亟需解决的难题。本文在综合国内外关于CAT研究的基础上,主要就计算机辅助公差设计领域的公差分析和公差优化分配两方面问题进行了研究和分析工作。主要研究内容如下:首先,对计算机辅助公差设计领域的相关理论和方法进行了整理和阐述,重点分析对比了公差分析的常用方法以及基于优化技术的公差分配技术理论。然后,分析了蒙特卡洛法的基本思想和特点,针对传统蒙特卡洛法收敛速度较慢的缺点,提出以通过构造拟随机数序列代替伪随机数列的拟蒙特卡洛法,给出了基于拟蒙特卡洛法计算封闭环尺寸和公差的具体实现流程,并借助matlab软件对实例装配尺寸链进行公差分析工作。然后将计算结果与传统蒙特卡洛法、概率法、极值法进行了对比,验证了蒙特卡洛法和拟蒙特卡洛法应用于公差分析问题上适用性,也表明了拟蒙特卡洛法相较于传统蒙特卡洛法在计算效率上的优势。最后,在质量损失成本的基础上,引入质量保证成本构成综合质量成本,构建了以最小加工成本和综合质量成本为优化目标,以装配功能要求、经济加工能力为约束条件的公差多目标优化分配模型;对基本引力搜素算法(GSA)进行了两点改进,设计了改进引力搜索算法(IGSA)的实现流程,在齿轮组件轴向尺寸链公差分配问题上实现了寻优计算,通过计算结果的分析和对比,验证了本文改进的模型和IGSA算法在解决公差优化分配问题上的优越性。
[Abstract]:The tolerance attribute of the product is the direct embodiment of the product processing and assembly precision, which not only directly affects the performance level of the product, but also determines to a great extent the manufacturing process and cost. The reasonable tolerance design in the design stage of the product can improve the assemblability of the product and guarantee the quality of the product. As one of the key technologies to realize the integration of CAD (CAD / CAD) and CAM (computer aided Manufacturing) (CAM), the development of CAT (computer aided tolerance Design) is lagging behind. The research work of CAT technology is still a difficult problem for domestic and foreign scholars and enterprises to solve. In this paper, two aspects of tolerance analysis and tolerance optimal allocation in the field of computer-aided tolerance design are studied and analyzed. The main contents are as follows: first of all, The related theories and methods in the field of computer-aided tolerance design are summarized and expounded. The common methods of tolerance analysis and the theory of tolerance distribution technology based on optimization technology are analyzed and compared. In this paper, the basic idea and characteristics of Monte Carlo method are analyzed. In view of the slow convergence speed of traditional Monte Carlo method, a pseudo Monte Carlo method is proposed to replace pseudorandom sequence by constructing quasi random number sequence. The realization flow of calculating the size and tolerance of the closed ring based on the quasi-Monte Carlo method is given, and the tolerance analysis of the assembly dimension chain is carried out with the help of matlab software. Then, the calculation results are compared with the traditional Monte Carlo method and the probability method. The extremum method is compared to verify the applicability of Monte Carlo method and quasi Monte Carlo method in tolerance analysis. It also shows that the quasi-Monte Carlo method is superior to the traditional Monte Carlo method in computing efficiency. On the basis of the cost of quality loss, the quality assurance cost is introduced to constitute the comprehensive quality cost, and the minimum processing cost and the comprehensive quality cost are taken as the optimization objectives, and the assembly function requirements are taken as the optimization goal. A multi-objective optimal allocation model of tolerance with economic processing capacity as constraint condition is proposed, and two improvements are made to the basic Gravity search algorithm (GSA), and the implementation flow of the improved Gravity search algorithm (IGSA) is designed. The optimization calculation is realized in the problem of tolerance assignment of gear components in axial dimension chain. Through the analysis and comparison of the calculation results, the superiority of the improved model and IGSA algorithm in solving the problem of tolerance optimization allocation is verified.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.7;F273

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