并联机床结构及误差分析研究

【作者】 彭用新；

【导师】 樊瑜瑾；

【作者基本信息】 昆明理工大学 ， 机械电子工程， 2006， 硕士

【摘要】 并联机床是知识密集型机电一体化制造装备，涉及机械、电子、自动控制、计算机、传感器等多学科领域，它是20世纪90年代问世的新型数控加工装备。尽管从理论上讲，并联机床比传统机床具有明显的优势，但从目前看，并联机床还有许多问题没有很好解决。主要包括并联机构理论、精度问题等方面，这成为制约并联机床商品化和产业化的瓶颈问题。并联机构构型问题是并联机构研究中的主要和基础性问题之一，少自由度并联机床的机构构型方法目前仍然是一个国际上公认的难题，还没有一个统一的普遍方法来解决。而由于并联机床误差关系复杂，虽然理论上应有高的精度，但实际应用中其精度还没有达到传统机床的精度水平。本文就这两方面进行了研究。本文首先针对并联机床的构型问题，提出一种基于广义坐标的描述支链末端运动的特殊坐标，研究了具有确定末端运动的并联机构支链。并在此基础上利用具有确定运动的支链提出一种并联机床机构构型方法。并进行了六自由度和一少自由度并联机构的构型研究。在运动分析上，采用矢量巨阵分析法，通过建立适当的坐标，得出一种简单的位置正解方法。在误差分析方面，围绕昆明机床的XNZ63并联机床原型机，用微分学原理与矢量矩阵相给合，对Stewart型并联机床的杆长误差以及上、下铰点安装误差做了分析，推导出并联机床机构杆长及铰点位置误差与系统位置精度和姿态位置精度之间的关系，得到一些结论。利用机器人学中的D-H方法，结合从运动学方程微分得到的结论，通过建立适当的辅助坐标系，推导出XNZ63原型机终端运动误差和铰链间隙误差间的映射关系，并进行仿真研究，得到工作空间范围内终端误差的分布规律。更多还原

【Abstract】 The research on PKM involves mechanical engineering, electronics, automation, computer, sensors and so on. It is a new kind of numeral control machining equipments that came into being in 1990’s. Although PKM has outstanding advantages when compared with traditional machine tools, it also has a lot of problems which include the principle of the mechanism design and accuracy and so on to be solved nowadays. This problem is the bottleneck for industrialization of this kind of machine tools. Type syntheses of parallel kinematics machine is the main problems of the research on PKM, and nowadays there is not a general way to solve the mechanism design problem of 5-DOF and even more less degree of freedom mechanism, which is to be seen as a hard problem in the word. PKM has more accuracy in theory, although, Because of the complex relationship that errors affect on the machine tool’ s accuracy, PKMs do not achieve the kinematic accuracy level of traditional machine tools in practical applications. So the research on the above problems is presented in this thesis.At first, in order to solve the type synthesis, A special coordinates to describe the motion features of the linkages based on the generalized coordinates are proposed in this paper. And the linkages which has specific motion are analyzed. And a structural method on the type synthesis of PKMs is introduced with the analysis on the linkages and the special coordinates. By using this method, a new 6-DOF and a new serial-parallel kinematics machine tool are obtained, which is just the one studied in this paper. As for the kinematics, the methods to get the direct kinematic solutions are discussed by using proper coordinates and matrix methods.As for the error analysis, taking the XNZ63 made by Kunming machine tool stock company as the structural mode, by using differential principle and matrix methods, a error analysis model of the machine is derived. Using the D-H convention and the conclusion from the derivation of kinematic equations, the mapping between the joint clearances and the terminal’s error is determined, and the distributing rules of terminal’s error in the workspace are obtained.更多还原