空间多环耦合机构数字化构型综合理论

发布时间：2017-12-31 18:43

本文关键词：空间多环耦合机构数字化构型综合理论　出处：《燕山大学》2014年博士论文　论文类型：学位论文

【摘要】：机构的构型创新是机械装备原始性创新的重要内容,构型综合是构型创新的有效手段。空间多环耦合机构包含多分支空间并联机构和空间耦合链机构两大类,具有刚度大、承载能力强、精度高等优点,在工业生产中有广泛的应用前景。现有的空间多环耦合机构构型综合方法主要采用手工枚举方式,效率较低,很难系统地综合数目极为庞大、形式变化多端的空间多环耦合机构,且综合的结果不便于存储和筛选。对于这些问题,基于计算机技术的数字化构型综合是有效的解决手段。本文以空间多环耦合机构为研究对象,研究它们的数字化构型综合理论。建立了并联机构的新字符描述,将螺旋的参数化表达与字符描述相结合,实现了分支运动螺旋系的自动求解。基于线性代数中的初等行变换,实现过约束数目的自动解算。通过分析含“未定几何关系”轴线之间相对自由度,实现了自由度瞬时性自动判别,最终实现了空间并联机构的自由度数字化自动分析。基于螺旋理论,证明了三自由度,四自由度和五自由度分支提供约束力或约束力偶的几何限定条件。通过程序生成轴线之间几何关系的组合并插入运动副字符,根据几何限定条件进行筛选,从而实现三自由度,四自由度和五自由度分支数字化构型综合,建立了上述三类分支的构型数据库。提出了空间并联机构的数字化构型综合方法,分别推导了九种少自由度对称和非对称并联机构的约束模式。研究了在给定约束模式下的构型综合过程,建立了各种少自由度并联机构的构型数据库,开发了人机交互的构型展示软件。基于建立的并联机构的构型数据库,分别提出了基于三自由度并联机构,四自由度并联机构和五自由度并联机构的机械装备新机型,分析了各种新机型的构型特点。以一类重要的空间耦合链机构(称为两层两环空间机构)为研究对象,基于运动螺旋方程,建立了耦合支链带来的耦合关系的数学模型。基于数学模型,提出了这类机构中刚性子结构的判别方法,建立了这类机构的自由度分析原理,并研究了这类机构自由度分析的数字化实现。基于两层两环空间机构的自由度分析原理,提出了这类机构的构型综合方法,对十四种少自由度两层两环空间机构进行了系统的综合,得到了大量的新型空间耦合链机构,并研究了这类机构构型综合的数字化实现。
[Abstract]:The configuration innovation of the mechanism is an important content of the original innovation of mechanical equipment. Configuration synthesis is an effective means of the configuration innovation. The spatial multi-ring coupling mechanism consists of two categories: the multi-branch spatial parallel mechanism and the spatial coupling chain mechanism. It has many advantages, such as high stiffness, high bearing capacity and high precision, so it has a wide application prospect in industrial production. The existing spatial multi-ring coupling mechanism configuration synthesis method mainly adopts manual enumeration, and the efficiency is low. It is very difficult to systematically synthesize a large number of spatial multi-loop coupling mechanisms with varied forms, and the results of synthesis are not easy to store and filter. Digital configuration synthesis based on computer technology is an effective solution. In this paper, the digital configuration synthesis theory of spatial multi-ring coupling mechanism is studied, and a new character description of parallel mechanism is established. The parameterized expression of helix is combined with the character description to realize the automatic solution of the branch motion helical system based on the elementary line transformation in linear algebra. By analyzing the relative degrees of freedom between axes containing "undetermined geometric relations", the instantaneous automatic discrimination of degrees of freedom is realized. Finally, the digital automatic analysis of the degree of freedom of the spatial parallel mechanism is realized, and the three degrees of freedom is proved based on the helical theory. Four degrees of freedom and five degrees of freedom branches provide binding or binding pairs of geometric constraints. The combination of geometric relations between axes is generated by the program and the kinematic pair characters are inserted and screened according to the geometric constraints. Thus, the digital configuration synthesis of three degrees of freedom, four degrees of freedom and five degrees of freedom branches is realized, the configuration database of the above three kinds of branches is established, and the digital configuration synthesis method of spatial parallel mechanism is put forward. The constraint modes of nine kinds of symmetric and asymmetric parallel mechanisms with less degrees of freedom are derived respectively. The configuration synthesis process under the given constraint mode is studied and the configuration database of various kinds of parallel mechanisms with less degrees of freedom is established. The configuration display software of man-machine interaction is developed. Based on the configuration database of the established parallel mechanism, the three-degree-of-freedom parallel mechanism is proposed. The new mechanical and equipment models of 4-DOF parallel mechanism and 5-DOF parallel mechanism. The configuration characteristics of various new models are analyzed. A kind of important spatial coupling chain mechanism (called two-layer two-ring space mechanism) is studied based on the motion helical equation. The mathematical model of coupling relation brought by coupling branching chain is established. Based on the mathematical model, the discrimination method of rigid substructure in this kind of mechanism is put forward, and the principle of degree of freedom analysis of this kind of mechanism is established. The digital realization of the freedom analysis of this kind of mechanism is studied. Based on the principle of the freedom analysis of the two-layer two-ring space mechanism, the configuration synthesis method of this kind of mechanism is put forward. In this paper, 14 kinds of space mechanisms with less degrees of freedom are systematically synthesized, and a large number of new spatial coupling chain mechanisms are obtained, and the digital realization of this kind of mechanism configuration synthesis is studied.
【学位授予单位】：燕山大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH112

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