Stiffness modeling of n(3RRlS) reconfigurable series-parallel manipulators by combining virtual joint method and matrix structural analysis

Chong Zhao, Hongwei Guo, Dan Zhang, Rongqiang Liu, Bing Li, Zongquan Deng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

24 Citations (Scopus)

Abstract

Stiffness is one of the critical performance indexes for robotic manipulators. In this study, a method for establishing the stiffness models of n(3RRlS) reconfigurable series-parallel manipulators (RSPMs) is proposed by combining the virtual joint method and matrix structural analysis. First, the constraint wrench system of the 3RRlS reconfigurable parallel manipulator (RPM) is obtained based on the reciprocal screw theory. Second, the stiffness matrices of the limbs along the axes of the constraint wrenches are analyzed using matrix structural analysis, and the overall stiffness matrix of the limbs is then assembled. Third, the stiffness matrices of the 3RRlS RPM and the n(3RRlS) RSPM are successively derived using the principle of virtual work. Finally, the theoretical and the finite-element-analysis deformations of the 3RRlS RPM and 3(3RRlS) RSPM are solved, and their average relative error is within 3.78%. It can be concluded that increasing actuation constraints can effectively improve the stiffness of manipulators in the directions of six degrees of freedom (DOFs) while increasing structural constraints can effectively improve the stiffness of manipulators in the directions of constrained DOFs.

Original languageEnglish
Article number103960
JournalMechanism and Machine Theory
Volume152
DOIs
Publication statusPublished - Oct 2020
Externally publishedYes

Keywords

  • Matrix structural analysis
  • Reconfigurable parallel manipulator
  • Reconfigurable series-parallel manipulator
  • Stiffness modeling
  • Virtual joint method

ASJC Scopus subject areas

  • Bioengineering
  • Mechanics of Materials
  • Mechanical Engineering
  • Computer Science Applications

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