机械产品几何精度设计中的三维偏差分析技术

发布时间：2018-03-03 12:18

  本文选题：几何公差　切入点：公差规范　出处：《北京理工大学》2014年博士论文　论文类型：学位论文

【摘要】：几何精度设计是保证机械产品质量的重要环节，贯穿于结构设计、装配设计和工艺设计过程之中，对提高产品性能和制造效率具有重要的意义。随着机械产品结构日趋复杂、装配精度要求不断提高以及三维数字化设计与制造技术应用的日益深入，三维偏差分析已成为产品研发中的热点。为此，本文开展了机械产品几何精度设计中的三维偏差分析技术研究，拟为几何精度设计和提高产品装配精度及一次装配成功率提供了理论基础和实现技术。 论文的主要研究内容如下： （1）阐述了本课题的研究背景，详细分析了公差建模、公差分析、公差综合和计算机辅助公差设计技术的研究现状，提出并总结了现有研究成果存在的问题与不足，给出了本课题的研究目标和意义。 （2）针对几何精度设计过程中几何公差表达不规范的问题，提出了基于多色集合理论的几何公差信息推理及其规范性验证方法。通过构建几何公差信息本体模型，提炼并总结了几何信息、方位信息、约束信息与公差信息之间的约束关系，提出了层次化的几何公差信息推理结构，并基于多色集合理论构建了该层次结构的多色集合模型，采用围道矩阵对信息之间的约束关系加以描述，给出了公差类型和附加符号推理算法，在确保基准体系合理的基础上实现了几何公差信息的规范性验证。 （3）针对零件之间装配成功率计算精确性不高的问题，提出了基于配合接触状态的定位优先级约束下零件装配成功率计算模型。在装配特征变动分析的过程中充分考虑了定位先后顺序的影响，并分别针对平行平面配合、圆柱面配合、圆锥面配合和球面配合等间隙配合，分析了配合接触状态下装配特征变动约束条件，构建了零件装配成功率计算模型，通过随机模拟装配特征的变动，实现了基于多对装配特征定位的两个零件之间装配成功率的精确计算。 （4）针对面向几何公差的装配偏差传递路线难以搜索的问题，提出了基于变动向量空间的装配偏差传递路线搜索方法。在全面地解析不同空间关系下特征之间理论约束方向的基础上，根据线性相关理论归纳了特征之间实际约束方向的求解算法，提出了基于变动向量空间模型的约束方向范围描述手段和偏差传递路线搜索算法，并给出了偏差传递路线的搜索流程，实现了三维偏差的装配偏差传递路线搜索。 （5）针对面向几何公差的装配精度预测效率较低的问题，提出了基于多自由度偏差分布的装配精度预测模型。通过构建几何误差分布统一模型，并根据几何误差与自由度偏差之间的关系，全面解析了公差域和配合间隙约束下平面、直线和点在多个自由度方向上偏差的分布，再经过对装配偏差累积模型进行协方差处理，，构建了基于自由度偏差分布的装配精度解析模型，实现了面向几何公差的装配精度和装配工艺能力指数的快速计算。 （6）针对工艺过程中定位基准转换引起的几何公差转换的问题，提出了基于公差变动矢量图的几何公差转换方法。构建了定位关系转换有向图及其数学模型，通过变动分析，建立了加工公差和基准漂移约束下目标特征的公差变动矢量图，提出了基于横截面的公差变动矢量图包围关系判定算法，推导了设计公差与加工公差的约束条件，实现了几何公差的直接转换。 （7）结合论文的研究成果以及相关科研课题，介绍了自主开发的公差信息管理与分析软件系统的总体架构、功能模块和软件界面，并以航天器舱段与设备装配为实例验证了系统的可行性和有效性。
[Abstract]:Geometric precision design is an important link to ensure the quality of mechanical products, through structural design, assembly design and process design, has an important significance to improve product performance and manufacturing efficiency. With the mechanical product structure is becoming increasingly complex, and continuously improve the assembly precision and the three-dimensional digital design and manufacturing technology is used widely, 3D deviation the analysis has become a hot topic in product research and development. Therefore, this paper carried out the 3D deviation of mechanical products in geometric precision design analysis technology research and implementation technology, to provide theoretical basis for the design of geometric precision and improve the precision of assembly and an assembly success rate.
The main contents of this paper are as follows:
(1) elaborated the research background of the subject, analyzed the research status of tolerance modeling, tolerance analysis, tolerance synthesis and computer aided tolerance design in detail, and put forward and summarized the existing problems and shortcomings of the existing research results, and gave the research objectives and significance of this topic.
(2) according to the geometric precision design of process tolerance expression is not regulated, presents the geometric tolerance information reasoning and normative verification method based on polychromatic sets theory. By constructing geometric tolerance information ontology model, refining and summarized the geometric information, position information, constraint relation between constraint information and tolerance information, put forward the hierarchical structure and geometric tolerance information reasoning, based on polychromatic sets theory to construct the hierarchical structure of the polychromatic set model, using contour matrix of constraint relations between information to describe the given tolerance types and additional symbolic reasoning algorithm, ensure reasonable benchmark system realizes geometric tolerance information standardization verify.
(3) the parts assembly success rate calculation accuracy is not high, the positioning of the contact state under precedence constraints with assembly success rate based on the calculation model. In the process of assembly feature change analysis considering influence of positioning sequence, and were aimed at the plane parallel with the cylinder with cone with the surface and spherical with clearance fit, analyzed with contact state changes of assembly feature constraints, construction assembly success rate calculation model, the stochastic simulation of assembly feature changes, realize the accurate calculation between the two parts of the assembly feature location based on assembly success rate.
(4) for assembly oriented deviation geometric tolerances route difficult to search problems, put forward the change of assembly deviation vector space search method based on the transmission line. Based on the comprehensive analysis of different spatial relations characteristic under the direction of the theory of constraints, algorithm according to the linear correlation theory summed up the direction of actual constraints among the features. The proposed constraint direction vector space model to describe the change means and deviation transfer route search algorithm based on the error and gives the route search process, realize 3D assembly deviation deviation route search.
(5) according to the assembly precision prediction efficiency oriented geometric tolerances with the problem of low prediction model is proposed based on multi degrees of freedom distribution assembly accuracy. By constructing geometric error distribution model, and according to the relationship between the geometric error and deviation of degree of freedom, a comprehensive analysis of the tolerance domain and the gap with the constraint plane. The distribution of the lines and points in multiple degrees of freedom direction deviation, and then after the assembly deviation cumulative model covariance processing, constructs the degrees of freedom distribution assembly accuracy based on the analytical model, the fast calculation for assembly precision and assembly process capability index of the geometric tolerances.
(6) the conversion conversion problem caused by geometric tolerances for positioning in the process of reference, put forward the conversion method of geometric tolerance changes based on the vector graph. Construct a directed graph based model transformation between positioning and mathematics, through change analysis, established the process tolerances and base drift under the constraint of target feature vector change tolerance the cross section of the tolerance, change vector relation decision algorithm based on the derived constraints on design tolerances and machining tolerances, realizes the direct conversion of geometrical tolerances.
(7) according to the research results and related research, introduces the overall architecture of independent development of tolerance information management and analysis software system, function module and software interface, and the assembly of spacecraft cabin and equipment as an example to validate the feasibility and validity of the system.

【学位授予单位】：北京理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH122


本文编号：1561003