基于虚拟样机的并联机构振动仿真分析

发布时间：2018-08-06 22:14

【摘要】：在加工制造行业日益发展的今天，越来越多的高精度、复杂加工出现在人们面前，特别是对于复杂曲面的加工对加工机床的要求更高。传统的串联机床由几级的悬臂部件铰接而实现最终的加工要求，但由于铰接的间隙与悬臂的变形的原因不能获得较高的结构刚度，而且误差会累积到执行端，严重的影响了加工的精度。而近年发展起来的并联机构正适应了这一需要，并联机构具有刚度高、承载能力强、结构紧凑的特点，与传统的机构形成了很好的互补，但并联机构连杆的变形及系统的振动仍是影响精度的主要原因。随着计算机技术的发展，特别是仿真技术的发展，现代机械产品的开发优化越来越依赖于计算机，本文运用ADAMS虚拟样机技术，以并联机床为例进行了简化机构模型的刚柔耦合建模和振动分析。通过对模型的振动分析得出对模型执行端影响较大的方面，并对模型结构进行改进，从而达到减小振动提高精度的目的。本文通过三维建模软件UG对并联机构的简化模型进行建立，根据实际的连接关系，将其装配成一个完整的传动系统。通过数据传递，将建立的装配模型导入到ADAMS中，建立传动装置各部件之间的运动约束关系，完成仿真的前期处理工作。然后通过对关键变形部件进行柔性体划分，对相应的刚性体予以替换，实现刚柔耦合模型的建立。通过仿真得到了各种条件下的振动模态，即固有频率、振型等特性，并针对不同的振动类型分别进行强迫振动分析，研究了各种振动的强迫振动响应特性。在建立完成多柔体仿真模型的基础上，通过对动平台添加刚度适当的柔索弹簧阻尼机构，，对运动机构进行优化处理。在对优化后的模型进行相同的激振输入做振动分析，比较优化前与优化后振动响应情况的变化，分析优化前后机构的特性变化，为以后的物理模型的建立提供依据。这对并联机床在以上领域的理论与实际研究都具有重要意义。
[Abstract]:With the increasing development of the manufacturing industry, more and more high precision and complex machining appear in front of people, especially for the complex surface processing of machine tools. Traditional series machine tools are hinged by several stages of cantilever parts to achieve the final processing requirements. However, due to the clearance of hinges and the deformation of the cantilever, the higher structural stiffness can not be obtained, and the errors will accumulate to the executive end. The precision of machining is seriously affected. The parallel mechanism developed in recent years meets this need. The parallel mechanism has the characteristics of high stiffness, strong bearing capacity and compact structure, which is complementary to the traditional mechanism. However, the deformation of the connecting rod and the vibration of the parallel mechanism are still the main reasons to affect the accuracy. With the development of computer technology, especially the development of simulation technology, the development and optimization of modern mechanical products depend more and more on computer. This paper uses ADAMS virtual prototyping technology. The rigid-flexible coupling modeling and vibration analysis of the simplified mechanism model are carried out with a parallel machine tool as an example. Through the analysis of the vibration of the model, it is found that there is a great influence on the executive end of the model, and the structure of the model is improved so as to reduce the vibration and improve the accuracy. In this paper, the simplified model of the parallel mechanism is established by using the 3D modeling software UG, and it is assembled into a complete transmission system according to the actual connection relationship. Through the data transfer, the assembly model is imported into ADAMS, and the motion constraint relationship between the components of the transmission device is established, and the pre-processing work of simulation is completed. Then, by dividing the key deformed parts into flexible bodies and replacing the corresponding rigid bodies, the rigid-flexible coupling model is established. The vibration modes under various conditions, namely, natural frequency, vibration mode and so on, are obtained by simulation. The forced vibration characteristics of different vibration types are analyzed separately and the forced vibration response characteristics of various kinds of vibration are studied. On the basis of establishing the simulation model of multi-flexible body, the motion mechanism is optimized by adding a flexible spring damping mechanism with appropriate stiffness to the moving platform. The vibration analysis of the optimized model is done with the same excitation input, and the changes of vibration response before and after optimization are compared, and the characteristics of the mechanism before and after optimization are analyzed, which provides the basis for the establishment of the physical model in the future. This is of great significance to the theoretical and practical research of PMT in the above fields.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP302;TP391.9

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