|
Abstract: With
the Stewart platform as an example, a new method is proposed to analyze
stiffness of parallel kinematic machines(PKM) based on analytical and
finite element analysis(FEA) means. In this method, FEA software is
used to simu-late the nonlinear contact deformation inside spherical
joints at first. A feature parameter is extracted from the FEA model and
considered in the stiffness matrix of the mechanism. This method solves
the problem of inability to treat joint stiffness in the analytical
model and its reliability is verified using FEA software. If joint
deformation is ignored in the analytical process to compute the
mechanism stiffness, the overall stiffness results will produce rather
large error. Based on the above analysis, quantitative study on
improving stiffness by active redundant leg is carried out with the
proposed method. The results show that in certain range of the
workspace, active redundant leg can increase stiffness of PKM
significantly.
Key words: Parallel kinematic machines(PKM)
Static stiffness Spherical joint
Finite element analysis(FEA)
CLC No: TG502
国家自然科学基金资助项目(50375010). Received 20051130, received in revised form 20060410
|