面向任意接触定位方案的定位误差分析算法

发布时间：2018-01-19 12:42

本文关键词： 机床夹具定位误差工件位置偏移接触副　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：在现代生产制造行业中,机床夹具被普遍广泛的使用,一方面是机床夹具可以很好的保证被加工的工件一直处于一个相对正确的位置上以满足必要的加工工艺要求;另一方面是如果把机床夹具单独看成一个系统,其本身具备的功能也比较强大,既能够适应于大批量产品的生产,也能满足一些特殊的、个性化的产品的生产。随着我国制造工业技术水平的不断提高,对机床夹具的要求也在不断的增加,所以对机床夹具的研究工作变的越来越重要。而机床夹具定位误差的大小可以很客观的表达出一套夹具系统能否满足加工工艺的要求,因此,研究如何进行高效、便捷、准确的计算夹具定位误差的方法对我国整体制造行业技术的进步具有深刻的含义。虽然传统的、经典的计算定位误差的方法有很多,具有代表性的比如极限位置法、平面尺寸链法、微分法等等,这些算法虽然原理简单,计算过程也不算非常复杂,但是均有着一个很大的困扰就是不具备一般通用性。换句话来说就是,计算某些或某种工况下机床夹具系统的定位误差只能使用特定的某种或某几种计算方法,而不是所有的计算方法都可以使用。在这种大的形势之下,研究一种具备通用性、非常利于数据库等实现自动化操作的定位误差的计算方法表现的非常有必要性。这一自动化计算的实现,对促进CAFD(Computer Aided Fixture Design)系统实用化进程是具有实际意义的。本文剖析了工件制造误差、定位元件制造误差与安装误差对工件位置偏移的影响规律,概括了工件和定位元件的接触副,构建了接触点位置变化的有向尺寸路径模型和有向尺寸链模型,将接触点位置变化描述为接触副尺寸误差。该方法不仅适用于单边接触式定位方案,也适用于任意边接触式定位方案。结合坐标转换技术,运用微分学建立把工件位置偏移、定位误差形容为接触点位置变化的函数的分析模型。考虑到接触副尺寸和角度的独立性原则,提出数据表格方法实现变量的独立性检查,确保工件位置偏移的正确计算。针对不同的夹具工件接触方式,提出统一的工件位置偏移模型,并利用接触点位置变化的有向尺寸路径模型和有向尺寸链模型,将接触点位置变化描述为接触副尺寸误差,最后使用表格求解法计算工件位置偏移。本文讨论了由定位误差计算工件位置偏移的问题,提出了工件夹具系统运动学分析模型,该论文从矢量环构建进行解算有一定的新意。以表的形式存储于数据库中,易于计算机编程实现定位误差的自动化分析。
[Abstract]:In the modern manufacturing industry, fixture is widely used. On the one hand, the fixture can ensure that the workpiece is always in a relatively correct position to meet the necessary processing requirements; On the other hand, if the machine tool fixture is considered as a system alone, its own functions are also relatively strong, which can be used in the production of large quantities of products, but also meet some special. The production of individualized products. With the continuous improvement of the technology level of manufacturing industry in China, the requirements for machine tools and fixtures are also increasing. Therefore, the research of machine fixture becomes more and more important. And the positioning error of machine fixture can objectively express whether a set of fixture system can meet the requirements of processing technology. The research on how to calculate the fixture positioning error efficiently, conveniently and accurately has profound meaning for the progress of the whole manufacturing industry in China. Although there are many traditional and classical methods to calculate the positioning error. Some representative methods such as limit position method, plane dimensional chain method, differential method, etc., these algorithms are simple in principle, and the calculation process is not very complicated. In other words, in other words, the positioning error of machine tool and fixture system can only be calculated by one or several special calculation methods under certain working conditions. Not all calculation methods can be used. In such a large situation, the study of a universal. It is very necessary to calculate the positioning error of automatic operation, such as database. It is of practical significance to promote the practical process of CAFD(Computer Aided Fixture Design system. This paper analyzes the manufacturing error of workpiece. The influence of manufacturing error and installation error of positioning element on the position deviation of workpiece is summarized. The directional dimension path model and directional dimension chain model of the position change of contact point are constructed. The change of contact point position is described as contact pair dimension error. This method is not only suitable for unilateral contact positioning scheme, but also suitable for arbitrary side contact positioning scheme. By using the differential calculus, an analytical model is established in which the position of the workpiece is offset and the positioning error is described as the change of the position of the contact point, taking into account the independence principle of the size and angle of the contact pair. A data table method is proposed to check the independence of the variables to ensure the correct calculation of the workpiece position offset, and a unified workpiece position migration model is proposed for different contact modes of the fixture workpiece. Using the directional dimension path model and the directed dimension chain model, the contact point position change is described as the contact pair dimension error. At last, the paper discusses the problem of calculating the workpiece position offset by the positioning error, and puts forward the kinematics analysis model of the workpiece fixture system. In this paper, it is new to solve the problem of vector loop construction. It is stored in database in the form of table, and it is easy to realize the automatic analysis of positioning error by computer programming.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG75

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