KINEMATICS AND STIFFNESS ANALYSIS OF A NOVEL 4-DOF OVER-CONSTRAINED PARALLEL MECHANISM WITH THREE LEGS, 450-460.
Xingchao Zhang, Hongbo Wang, Yu Rong, Jianye Niu, Junjie Tian, and Yuansheng Ning
Keywords
Parallel mechanism, over-constrained, kinematics analysis, stiffness analysis
Abstract
This paper studies the kinematics and stiffness of a novel 4-degree-
of-freedom (DOF) over-constrained parallel mechanisms (PMs).
First, a novel over-constrained 2RPU+PRPU PM consisting of two
revolute–prismatic–universal (RPU) type legs and one prismatic–
revolute–prismatic–universal (PRPU) type leg is proposed, where P,
U, and R represent the prismatic joint, universal joint, and revolute
joint, respectively. Next, the configuration of the PM is described,
the velocity constraint equation of 2RPU+PRPU PM is established,
and based on this, the DOF of this PM is analysed. Then,
the kinematic models are established, the kinematic performance
indexes are established using the screw theory, and the kinematic
performance of the 2RPU+PRPU PM is analysed according to these
indexes. Finally, the stiffness model of the 2RPU+PRPU PM is
deduced using the principle of virtual work and the deformation
decomposition method. Meanwhile, the stiffness performance maps
of the mechanism under different external loads are obtained based
on this model. This work is expected to provide a new idea for the
design of PMs.
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