Optics and Precision Engineering, Volume. 25, Issue 11, 2904(2017)
Stiffness and natural frequency of a (2PRR)2+R planar parallel mechanism
A novel 5-degree-of-freedom (DOF) hybrid serial-parallel manipulator was proposed. The kinematics of Parallel Mechanism (PM) of the 5-DOF hybrid manipulator was analyzed. The PM is a 3-DOF (one translational DOF and two rotational DOFs) metamorphic planar PM (2PRR)2+R with two different types of configurations: actuation redundancy and kinematic redundancy. Firstly, the kinematics model of the 3-DOF planar PM was established. Then, the stiffness matrix of the planar PM was obtained on the basis of kinematics analysis and the mass matrix was obtained by solving each equivalent component mass of the planar PM. Furthermore,the system dynamic equation was established through combining the stiffness matrix and mass matrix, and the natural frequency equation was obtained incidentally based on the dynamic equation. Finally, the stiffnesses and natural frequencies for the redundant and non-redundant planar PMs were analyzed and compared by numerical simulation. The results show that the maximum extend ranges of the stiffness around Z-axis and the first-order natural frequency reach 88.46% and 31.50%, respectively; and the minimum extend ranges of the stiffness along X-axis and the second-order natural frequency reach 52.34% and 1.90%, respectively. Thus, the stiffness and natural frequency of the planar PM have been obviously improved by adding actuation redundancy.
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ZHANG Dong-sheng, XU Yun-dou, YAO Jian-tao, ZHAO Yong-sheng. Stiffness and natural frequency of a (2PRR)2+R planar parallel mechanism[J]. Optics and Precision Engineering, 2017, 25(11): 2904
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Received: Mar. 31, 2017
Accepted: --
Published Online: Jan. 17, 2018
The Author Email: Dong-sheng ZHANG (ysuzds@163.com)