A unified framework for tolerance analysis of planar and spatial mechanisms using screw theory
A unified framework for tolerance analysis of planar and spatial mechanisms using screw theory
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DOI：
10.1016/j.mechmachtheory.2013.06.001
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发表时间：
2013-11
影响因子：
5.2
通讯作者：
U. Kumaraswamy;M. Shunmugam;S. Sujatha
中科院分区：
文献类型：
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作者：
U. Kumaraswamy;M. Shunmugam;S. Sujatha
由给定机构的选定点所跟踪的路径的运动精度受制造误差的影响，所述制造误差引起连杆长度和关节间隙的变化。机构公差分析是指找出机构中给定点由于制造误差而偏离标称轨迹的过程。本文提出了一种新的应用螺旋理论分析机构的运动精度与连杆长度和关节间隙的变化。通过对平面四杆机构的公差分析，验证了该方法的可行性。遵循国际标准的意图，在正常方向上量化与标称路径的偏差，这从实际角度来看更有意义。所提出的方法的空间机构的适用性证明了使用一个串联的机械手与三个转动关节，并有一个关节误差。本文提出的统一框架可以方便地应用于闭环和开环串联机器人。设计人员可以使用这种分析的结果来指定公差，以实现所需的运动精度。
Kinematic accuracy of path traced by a chosen point of a given mechanism is affected by manufacturing errors that cause variation in link lengths and joint clearances. Tolerance analysis in mechanisms refers to a process of finding out deviation from nominal path of the given point in the mechanism due to the manufacturing errors. In this paper, a new application of screw theory is proposed to analyze the kinematic accuracy of the mechanisms with variations in link lengths and joint clearances. Potential of the proposed approach is demonstrated by its application to the tolerance analysis of four-bar planar mechanisms. Following the intent of the international standard, the deviation from nominal path is quantified in normal direction which is more meaningful from a practical perspective. Applicability of the proposed approach to a spatial mechanism is demonstrated using a serial manipulator with three-revolute joints and having one joint-error. The unified framework presented in this paper can be applied conveniently for closed as well as open loop serial manipulators. Designers can use the results of such analysis to specify the tolerances to achieve a desired degree of kinematic accuracy.