关于3-PRS并联机构动刚度及静刚度模型的研究

发布时间：2018-05-27 01:17

本文选题：并联机构 + 动刚度　；参考：《河北工程大学》2014年硕士论文

【摘要】：近些年来，随着全球生产力的进一步提高，能够适应更为复杂的生产环境和满足更为多样化的市场需求的多功能机构和新型系统，成为了机械制造业争相探索和研究的方向。此时并联机构应运而生，相对于串联机构来说，它是一种新型的机构，它的优点主要在于其具有更高的刚度、更高精度以及更小的误差，而这些优点恰好满足了现代机械追求的目标，才使得并联机构得到广泛的应用。在并联机构中其刚度分析及性能评价是并联构型装备结构设计的重要内容，，如何能找到适合概念设计需求的刚度解析建模方法与评价方法，研究满足详细设计需求的整机刚度有限元快速精确建模方法及实验方法，以期为并联构型装备设计提供更为准确的刚度分析及性能评价模型，是摆在机械制造商面前的一大挑战。这也是本文的主要研究内容。本文以3-PRS并联机构为研究模型，首先对其进行了运动学分析，得到了此模型的雅克比矩阵，通过其雅克比矩阵建立了此模型的传统刚度矩阵模型。应用有限元软件ANSYS Workbench对3-PRS并联机构进行了全面的动力学分析。在模态分析中得到的是其固有频率和振型图。谐响应分析得到其承受载荷后的频率图。瞬态动力学分析最终得到的是此模型在运动过程中的不同时间、不同位姿时的刚度，即其动刚度。此种方法避免了需要针对不同位形对有限元模型进行网格重划和解算。选择对3-PRS并联机构有较大影响的上平台半径、铰链中转动杆的横截面直径以及铰链中移动杆的横截面边长为研究对象，应用正交试验的方法，对具有代表性的尺寸数据进行组合，建立正交表。应用ANSYS Workbench软件对正交表中的尺寸组合进行静力学分析，得到其静刚度。应用最小二乘法对最终的正交表中的数据进行拟合，得到两个刚度回归模型，挑选一种最佳的回归模型。应用MINITAB软件对3-PRS并联机构的刚度模型进行验证，并进行最佳子集回归分析、逐步回归分析、前向选择回归分析以及后向淘汰回归分析。应用MATLAB软件得到单因素以及双因素对于3-PRS并联机构的影响情况。全面的验证分析为今后对于并联机构的刚度研究提供新的方向和依据。
[Abstract]:In recent years, with the further improvement of global productivity, the multi-functional institutions and new systems, which can adapt to more complex production environments and meet more diversified market demand, have become the direction of the exploration and research of the machinery manufacturing industry. The main advantages of the mechanism are that they have higher stiffness, higher accuracy and smaller errors. These advantages just meet the goal of modern machinery and make the parallel mechanism widely used. In parallel mechanism, its stiffness analysis and performance evaluation are important contents of the structure design of parallel configuration equipment. In order to provide more accurate stiffness analysis and performance evaluation model for the design of parallel configuration equipment, the rigid analytical modeling method and evaluation method suitable for the requirement of conceptual design can be found to meet the detailed design requirements, and it can provide more accurate stiffness analysis and performance evaluation model for the design of parallel configuration equipment. Challenge. This is also the main research content of this article.
In this paper, the 3-PRS parallel mechanism is used as the research model. First, the kinematics analysis is carried out, and the Jacobian matrix of the model is obtained. The traditional stiffness matrix model of the model is established by its Jacobian matrix.
The finite element software ANSYS Workbench is used to carry out a comprehensive dynamic analysis of the 3-PRS parallel mechanism. In the modal analysis, the natural frequency and vibration pattern are obtained. The harmonic response analysis is used to obtain the frequency chart after the load is subjected. The transient dynamic analysis is finally obtained by the different time and position of the model in the movement process. This method avoids the need to remeshing and computing the finite element model for different configurations.
The radius of the upper platform which has great influence on the 3-PRS parallel mechanism, the cross section diameter of the hinge in the hinge and the cross section length of the movable bar in the hinge are studied. The orthogonal test is used to combine the representative size data with the orthogonal test. The size group in the orthogonal table should be used by the ANSYS Workbench software. The static stiffness is analyzed and the static stiffness is obtained. Using the least square method to fit the data in the final orthogonal table, two stiffness regression models are obtained, and the best regression model is selected.
The stiffness model of 3-PRS parallel mechanism is verified by MINITAB software, and the optimal subset regression analysis, stepwise regression analysis, forward selection regression analysis and backward elimination regression analysis are carried out. The effect of single factor and double factor on 3-PRS parallel mechanism is obtained by MATLAB software. The comprehensive verification analysis is for the future. The stiffness research of parallel mechanism provides new direction and basis.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH112

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