Mobility Change in Two Types of Metamorphic Parallel Mechanisms
Mobility Change in Two Types of Metamorphic Parallel Mechanisms
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DOI：
10.1115/1.3211023
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发表时间：
2009-11
期刊：
影响因子：
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通讯作者：
D. Gan;J. Dai;Q. Liao
中科院分区：
文献类型：
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作者：
D. Gan;J. Dai;Q. Liao
本文提出了一种新的关节——rT关节，并提出了两种由该关节组成的变质并联机构。在第一种类型中，机构通过将所有分支中的rT关节变为不同的构型来改变其拓扑结构。这种迁移率的变化通过两种情况来完成，一种是3(rT)PS变形并联机构，其迁移率从3到6不等，另一种是3(rT)P（rT）并联机构，其具有各种构型，包括纯平移、纯旋转和迁移率4。在第二种类型中，在并联机构中添加带有rT关节的中心支柱。机构的可变迁移率源于中心（rT）P（rT）支柱的拓扑变化。这在3SPS-1 (rT)P（rT）变质并联机制中得到说明，该机制使其迁移率从4变为5。迁移率分析表明，各分支局部迁移率的变化会导致平台迁移率的变化，从而实现一个变质过程。这种特殊的分析通过在迁移率分析中引入局部迁移率因子，导致改进的Grubler-Kutzbach准则的进步。
This paper presents a new joint coined as the rT joint and proposes two types of metamorphic parallel mechanisms assembled with this rT joint. In the first type, the mechanism changes its topology by turning the rT joints in all limbs into different configurations. This change in mobility is completed by two cases illustrated by a 3(rT)PS metamorphic parallel mechanism having variable mobility from 3 to 6 and a 3(rT)P(rT) parallel mechanism having various configurations including pure translations, pure rotations, and mobility 4. In the second type, a central strut with the rT joint is added in a parallel mechanism. The variable mobility of the mechanism results from the topological change of the central (rT)P(rT) strut. This is illustrated in a 3SPS-1 (rT)P(rT) metamorphic parallel mechanism, which changes its mobility from 4 to 5. It is demonstrated in mobility analysis that the change in local mobility of each limb results in the change in the platform mobility that a metamorphic process can be achieved. This particular analysis leads to advancement of improved Grubler-Kutzbach criterion by introducing the local mobility factor in the mobility analysis.