Elastodynamic Modeling and Analysis for an Exechon Parallel Kinematic Machine
Elastodynamic Modeling and Analysis for an Exechon Parallel Kinematic Machine
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Exechon 并联运动机的弹性动力学建模与分析
DOI：
10.1115/1.4030938
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发表时间：
2016-03
影响因子：
4
通讯作者：
Jin Yan
中科院分区：
文献类型：
--
作者：
Zhang Jun;Zhao Yan Q;Jin Yan
Exechon并联机床作为一种新型的并联机床，由于其概念性的高性能，引起了学术界和工业界的广泛关注。然而，由于Exechon PKM结构和运动学的复杂性，其动力学行为尚未得到彻底研究。为了识别Exechon并联机床的动态特性，本文采用子结构综合技术建立了并联机床的弹性动力学模型。Exechon并联机床根据其结构特点分为动平台子系统、定基座子系统和三个分支子系统。肢体子系统的运动微分方程推导出通过有限元（FE）配方通过模拟复杂的肢体结构作为一个空间梁与相应的几何截面。同时，将转动副、万向副和球副简化为具有等效刚度和几何中心质量的虚拟集中弹簧。由于动平台具有较高的刚度，将动平台视为刚体，利用牛顿第二定律推导了动平台的运动微分方程。在引入平台与杆件变形协调条件后，推导了Exechon并联机床的运动微分方程。特征方程的解决方案导致的固有频率和相应的模态振型的并联机床在任何典型的配置。为了快速预测系统的动力学行为，提出了一种数值计算系统固有频率分布的算法。仿真结果表明，由于结构的对称性，结构的低阶固有频率具有很强的位置依赖性，并呈轴对称分布。在最后阶段，进行参数分析，以确定结构，尺寸和刚度参数对系统的动态特性的影响，为Exechon并联机床的优化设计和性能改进提供有用的信息。所提出的弹性动力学建模方法和动力学分析过程只需稍加修改即可推广到其它过约束并联机床。
As a newly invented parallel kinematic machine (PKM), Exechon has attracted intensive attention from both academic and industrial fields due to its conceptual high performance. Nevertheless, the dynamic behaviors of Exechon PKM have not been thoroughly investigated because of its structural and kinematic complexities. To identify the dynamic characteristics of Exechon PKM, an elastodynamic model is proposed with the substructure synthesis technique in this paper. The Exechon PKM is divided into a moving platform subsystem, a fixed base subsystem and three limb subsystems according to its structural features. Differential equations of motion for the limb subsystem are derived through finite element (FE) formulations by modeling the complex limb structure as a spatial beam with corresponding geometric cross sections. Meanwhile, revolute, universal, and spherical joints are simplified into virtual lumped springs associated with equivalent stiffnesses and mass at their geometric centers. Differential equations of motion for the moving platform are derived with Newton's second law after treating the platform as a rigid body due to its comparatively high rigidity. After introducing the deformation compatibility conditions between the platform and the limbs, governing differential equations of motion for Exechon PKM are derived. The solution to characteristic equations leads to natural frequencies and corresponding modal shapes of the PKM at any typical configuration. In order to predict the dynamic behaviors in a quick manner, an algorithm is proposed to numerically compute the distributions of natural frequencies throughout the workspace. Simulation results reveal that the lower natural frequencies are strongly position-dependent and distributed axial-symmetrically due to the structure symmetry of the limbs. At the last stage, a parametric analysis is carried out to identify the effects of structural, dimensional, and stiffness parameters on the system's dynamic characteristics with the purpose of providing useful information for optimal design and performance improvement of the Exechon PKM. The elastodynamic modeling methodology and dynamic analysis procedure can be well extended to other overconstrained PKMs with minor modifications.
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DOI：
10.1007/s00170-013-5482-z
发表时间：
2014-03
期刊：
The International Journal of Advanced Manufacturing Technology
影响因子：
--
作者：
Z. Bi
通讯作者：
Z. Bi
DOI：
10.1115/1.4027315
发表时间：
2014-08
影响因子：
4
作者：
Hay Azulay;J. Mills;B. Benhabib
通讯作者：
Hay Azulay;J. Mills;B. Benhabib
影响因子：
10.4
作者：
Li, Yangmin;Xu, Qingsong
通讯作者：
Xu, Qingsong
DOI：
10.1243/095440505x30177
发表时间：
2005-03
期刊：
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture
影响因子：
--
作者：
M. Terrier;M. Giménez;J. Hascoët
通讯作者：
M. Terrier;M. Giménez;J. Hascoët
影响因子：
10.4
作者：
Bi, Z. M.;Jin, Y.
通讯作者：
Jin, Y.