Non-singular transitions between assembly modes of 2-DOF planar parallel manipulators with a passive leg
Non-singular transitions between assembly modes of 2-DOF planar parallel manipulators with a passive leg
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DOI：
10.1016/j.mechmachtheory.2014.02.014
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发表时间：
2014-07
影响因子：
5.2
通讯作者：
Fabio DallaLibera;H. Ishiguro
中科院分区：
文献类型：
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作者：
Fabio DallaLibera;H. Ishiguro
在并联机器人领域，不通过奇异位形而改变装配模式的可能性是众所周知的。以平面三自由度机器人为例，详细研究了这种过渡。研究了由两个RRR腿驱动、一个被动腿约束的2自由度并联机器人。它首先表明，当平台的运动被约束到旋转和平移沿着一个单一的方向，非奇异的装配模式转换是可能的。求解了该机构的运动学正逆问题。奇异性条件被写在明确的形式和几何解释。然后给出了非奇异装配模式转换的数值例子。随后，本文证明，如果平台，而不是限制到平移运动，非奇异装配模式转换成为不可能的。最后给出了将结果推广到更广泛的一类2自由度平面机器人的评论。
In the field of parallel manipulators, the possibility of changing assembly mode without passing through a singular configuration is well known. This kind of transitions was studied in detail for planar 3-DOF manipulators. This paper focuses on 2-DOF parallel manipulators actuated by two RRR legs and constrained to a 2-DOF motion by a passive leg. It first shows that when the platform movement is constrained to rotations and translations along a single direction, nonsingular assembly mode transitions are possible. The direct and inverse kinematic problems of the mechanism are solved. The singularity conditions are written in explicit form and geometrically interpreted. Numerical examples of nonsingular assembly mode transitions are then given. Subsequently, the paper proves that if the platform is instead constrained to translational motions, nonsingular assembly mode transitions become impossible. Remarks on the generalization of the results to a wider class of 2-DOF planar manipulators are finally given.