两种含平面分支六自由度并联机构的弹性变形与刚度研究

发布时间：2018-04-16 11:16

本文选题：六自由度 + 平面分支　；参考：《燕山大学》2016年硕士论文

【摘要】：在现代并联机构领域中,相对于少自由度并联机构而言,六自由度并联机构具有刚度大、惯性低、结构紧凑、不易产生形变等优点,因此六自由度并联机构越来越受到专家学者的关注,应用范围也越来越广。闭环结构的提出,使六自由度并联机构在结构上更加简单、紧凑,同时它的刚度与灵活性也得到了提高。本文以两种六自由度并联机构为研究对象,机构中平面分支相对于底座运动方式的不同导致了两种机构在结构上的差异,因此它们在工作空间、刚度和应用场合等方面有所不同,为了进一步了解机构的性能,本文研究了这两种机构在受载情况下的弹性变形与刚度,主要研究内容如下:首先,根据计算机辅助法建立了机构的模拟线框图与实体模型,同时根据矢量法计算了两种并联机构的速度雅克比矩阵以及力雅克比矩阵,用于计算机构刚度。其次,求解了机构的位置反解、驱动力以及驱动杆的弹性变形,在考虑平面分支上、下横梁变形的前提下,求解了机构分支刚度矩阵。结合虚功原理与雅克比矩阵求解了机构整体的刚度矩阵,并计算了机构动平台中心变形理论值,发现机构具有良好的刚度性能。最后,对机构进行了有限元模拟与分析,从仿真结果中得出了机构动平台中心变形的模拟值,将其与理论值进行对比验证,证明了理论计算结果的正确性。此外,为了避免机构在工作中产生共振与有害振型,对两种机构进行了模态分析,得出其固有频率,发现机构低阶固有频率较高不易产生共振。
[Abstract]:In the modern field of parallel mechanism, compared with the less degree of freedom parallel mechanism, the six degree of freedom parallel mechanism has high stiffness, low inertia, compact structure, easy to produce deformation etc., so the six degree of freedom parallel mechanism has attracted more and more attention of the experts and scholars, more and more wide range of applications. The closed loop structure. The six degree of freedom parallel mechanism in the structure is more simple, compact, and its rigidity and flexibility is improved. In this paper, two kinds of six DOF parallel mechanism as the research object, in plane relative to the base branch motion modes resulted in different two kinds of mechanism in structure, so they are in the working space, stiffness and application situation of different areas in order to further understand the mechanism of the performance, this paper researches the two institutions in the load cases of elastic deformation and stiffness, the main research contents are as follows: First of all, according to the computer aided method is established to simulate the mechanism diagram and entity model, and according to the vector calculation method of two kinds of parallel mechanism of Jacobian matrix and force Jacobian matrix for computer structure stiffness. Secondly, the inverse position solution of the driving force, and the driving rod elastic deformation, considering the plane the branch, under the premise of the beam deformation, solving branch stiffness matrix. According to the principle of virtual work and solving the Jacobian matrix stiffness matrix of the whole mechanism, mechanism of motion platform deformation theory is calculated, that mechanism has rigidity good performance. Finally, the mechanism was analyzed by finite element simulation and from the analysis, the simulation results obtained in simulation of mechanism motion platform deformation values, which were compared with the theoretical value to verify, prove the validity of the theoretical results. In addition, in order to avoid Resonances and harmful vibration modes are generated in the work. Modal analysis of the two mechanisms is made, and the natural frequencies are obtained. It is found that the low natural frequencies of the mechanism are relatively high, and it is not easy to generate resonance.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH112

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