标题: 多连杆机构的振动研究
A Study on Vibration of a Multilink Mechanism
作者: 陈真蓉
Chen-Jung Chen
吕宗熙
Tzong-Shi Liu
机械工程学系
关键字: 机构振动;连杆结构;动态分析;Mechanism Vibration;Linkage Mechanism;Dynamic Analysis
公开日期: 2002
摘要: 四连杆式二维运动机构可以和二维光学尺搭配成高精度长行程的二维定位系统。本研究旨在探讨此机构进行急进急停时发生的暂振问题。首先使用有限元素软体ANSYS,建立参数式模型,包括滑轨、连杆和握爪平台,进行静态和模态分析,获得振动模态和自然频率的分布,而所计算出的模态资料进一步汇入多体机械系统分析软体DADS,进行急动和急停的挠性机构动态分析,观察二维定位系统的各方向暂振,另外还设定不同的设计参数进行模拟,以及改变机构设计,比较其振动量。本研究根据分析的结果发现,此机构若欲达到nm的定位精度,其振动量似乎还是稍嫌大了一点,另外,其连接握爪的平台沿铅直Y方向的角速度特别显着,而这表示连接握爪的平台并不与滑轨保持平行,会危及精密量测;最后观察每个作动的频谱,可发现第8、18、19模态很容易会被激发。
A two-dimensionally positioning system capable of long traverse distance of motion is made up of a multilink mechanism and a two dimensional optical grating. The objective of this study is to investigate vibration of the multilink mechanism undergoing sudden moving and sudden stop. The finite element model in ANSYS contains a track, links, and a stage. Static analysis and modal analysis are carried out. Modal data is further used in a multibody dynamic analysis software DADS for flexible mechanism simulation. This study investigates vibration source and improve mechanism design to reduce vibration. Several conclusions can be deduced from the simulation results. Due to vibration nanometer precision is unattainable. The vertical angular velocity is found significantly faster than the horizontal angular velocity. Therefore, the stage and the track don’t remain parallel to each other. Frequency spectra exhibited the eighth, the eighteenth and the nineteenth resonance mode are always easily excited.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT910489064
http://hdl.handle.net/11536/70820
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