基于结合面误差建模的装配精度预测与优化研究

发布时间：2019-05-17 02:35

【摘要】：本文以实现复杂装配体的精度预测及优化为目的。在分析和研究了国内外的装配体误差建模方法、装配体误差累积与传递机理、机械产品的可靠性理论以及公差优化方法的基础上,详细阐述了多公差耦合作用下零件几何要素的误差建模方法,分析了结合面的误差形成机理及误差传递属性,提出了复杂装配体误差传递路径的求解方法,建立了装配体误差模型,实现了装配精度预测与公差优化。在此基础上,提出了数字化环境下精度设计系统的框架与实现方法,开发了精度设计软件系统平台。论文的主要内容如下:(1)建立了多公差耦合作用下零件几何要素的误差模型。采用小位移旋量法描述几何要素的误差变动。根据常见几何要素的多公差耦合情况,建立了对应的误差变动不等式与约束不等式。在此基础上,采用蒙特卡洛法模拟实际加工误差,求得了几何要素各误差分量的实际变动区间带宽,奠定了结合面误差求解的重要基础,并通过响应面法建立了几何要素误差分量实际变动区间带宽与公差之间的显式函数关系,为提高后文公差优化的效率提供了重要保障。(2)提出了结合面误差建模方法,分析了结合面误差传递属性。提出了以结合面为基础的装配体误差分析方法,根据结合面对误差的累积与传递作用,从误差累积角度分析了各类结合面误差的累积形成机理,从误差传递角度分析了不同结合面对零件的定位约束作用,给出了各类结合面的误差传递属性。根据相邻结合面间的关联关系,讨论了结合面组误差传递属性的求解方法。鉴于并联结合面误差传递属性间的相互影响,提出了以装配定位优先级为依据的并联结合面实际误差传递属性求解方法,阐述了并联结合面组误差建模的流程,为建立装配体误差模型奠定了基础。(3)提出了基于JSS矩阵的装配体误差传递路径求解方法。分析了复杂装配关系的描述需求,以多色集合理论为基础,采用结合面符号替代装配关系多色集合矩阵中的布尔型元素值,建立了可描述装配体组成、装配关系、结合面几何类型、连接方式、配合性质等多维信息的结合面符号矩阵(JSS矩阵)。提出了基于JSS矩阵的装配体误差传递路径搜索方法,实现了装配体主导误差传递路径的求解,有效降低了装配体误差分析的复杂性,为装配体误差建模提供了重要依据。在此基础上,讨论了支持多层次复杂装配体误差传递路径求解的多重关联JSS矩阵法。(4)实现了装配体的精度预测与公差优化。以结合面误差模型与装配体主导误差传递路径为基础,建立了装配体误差模型,实现了装配体的精度预测。讨论了装配精度的可靠性分析方法,根据装配体的精度要求,以装配精度可靠度等为约束条件,以成本最低为目标,结合动态惩罚函数法与遗传算法,实现了装配体公差优化,从而在满足精度要求的前提下,提高了加工经济性。(5)验证了装配体误差模型的预测效果,开发了精度设计软件系统。通过高精度数控磨床的测量试验,验证了装配体误差模型的预测精度。针对现有三维精度设计信息的表达方式存在的问题,提出了集成标注表达方法。以实现数字化精度设计为目标,提出了精度设计系统的框架,介绍了主要功能模块。以ACISHOOPS为平台开发了支持精度设计信息三维标注、装配过程规划与信息管理以及装配精度分析等功能的软件系统,并借助该软件系统完成了典型零件精度设计信息的三维标注与龙门导轨磨床的装配过程规划。
[Abstract]:The purpose of this paper is to realize the precision prediction and optimization of complex assembly. Based on the analysis and research of the method of the assembly error modeling at home and abroad, the error accumulation and transmission mechanism of the assembly, the reliability theory of the mechanical product and the tolerance optimization method, the error modeling method of the part geometry under the multi-tolerance coupling is described in detail. In this paper, the error forming mechanism and the error transfer attribute of the combined surface are analyzed, and the method for solving the error propagation path of the complex assembly is proposed, and the assembly error model is established, and the assembly accuracy prediction and the tolerance optimization are realized. On this basis, the framework and implementation method of the precision design system under the digital environment are put forward, and the software system platform of precision design is developed. The main contents of the thesis are as follows: (1) The error model of the part geometry under the multi-tolerance coupling is established. The error variation of the geometric elements is described by means of the small-displacement rotation method. According to the multi-tolerance coupling of common geometric elements, the corresponding error variation inequality and the constraint inequality are established. On this basis, the actual machining error is simulated by the Monte Carlo method, and the actual variation interval bandwidth of each error component of the geometric element is obtained, which lays the important foundation for solving the joint surface error. And the explicit function relation between the bandwidth and the tolerance of the actual variation interval of the geometric element error component is established through the response surface method, and the important guarantee is provided for improving the efficiency of the following tolerance optimization. (2) The joint surface error modeling method is proposed, and the error transfer property of the joint surface is analyzed. The error analysis method of the assembly body based on the combination surface is put forward. Based on the accumulation and transfer function of the combined face error, the accumulative formation mechanism of all kinds of joint surface errors is analyzed from the error accumulation angle, and the positioning and restraining effect of the different combination face parts is analyzed from the error transfer angle. The error transfer property of all kinds of bonding surfaces is given. Based on the relation between the adjacent binding surfaces, the method of solving the error transfer attribute of the combination surface group is discussed. In view of the mutual influence between the error transfer properties of the parallel combination surface, a method for solving the actual error transfer property of the parallel combination plane based on the assembly and positioning priority is put forward, and the flow of the parallel combination surface group error modeling is described, which lays a foundation for building the assembly error model. (3) The method for solving the error propagation path of the assembly based on the JSS matrix is proposed. The description requirement of complex assembly relation is analyzed. Based on the theory of multi-color set, the Boolean element value in the multi-color set matrix is replaced by the combination surface symbol, and the composition, assembly relation, joint surface geometry type and connection mode of the assembly body can be described. The combined surface symbol matrix (JSS matrix) of multi-dimensional information such as the matching property. The method for searching the error propagation path of the assembly body based on the JSS matrix is put forward, the solution of the main error propagation path of the assembly body is realized, the complexity of the error analysis of the assembly body is effectively reduced, and an important basis for modeling the error of the assembly body is provided. On this basis, the multi-correlation JSS matrix method for multi-level complex assembly error transfer path solution is discussed. And (4) the accuracy prediction and the tolerance optimization of the assembly body are realized. Based on the combined surface error model and the main error transfer path of the assembly body, the assembly error model is established, and the accuracy prediction of the assembly body is realized. The reliability analysis method of assembly accuracy is discussed. According to the accuracy requirement of the assembly, the assembly accuracy reliability and the like are the constraint conditions, the cost is the lowest, the dynamic penalty function method and the genetic algorithm are combined, and the assembly tolerance optimization is realized. So that the processing economy is improved on the premise of meeting the precision requirement. (5) The prediction effect of the assembly error model is verified, and the precision design software system is developed. The prediction accuracy of the assembly error model is verified by the measurement test of the high-precision numerical control grinding machine. Aiming at the problems existing in the expression of the existing three-dimensional precision design information, an integrated annotation expression method is proposed. In order to realize the digital precision design as the goal, the frame of the precision design system is put forward, and the main function modules are introduced. Taking the ACISHOOPS as the platform, the software system, which supports the functions of the three-dimensional dimension of the precision design information, the process planning and information management of the assembly process, and the assembly precision analysis, is developed, and the assembly process planning of the three-dimensional dimension of the typical part precision design information and the gantry guide rail grinding machine is completed by means of the software system.
【学位授予单位】：湖南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG95

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