Topology design of a 2-DOF 1T1R mechanism with redundant branch chain and the impact of active joint selection on performance
LI Ju
SHE Junjie
SHEN Huiping
MENG Qingmei
ZHU Xiaorong
Abstract：[Objective]To explore the method for selecting actuated joints in parallel mechanisms with redundant branch chains,a symmetric 3-limb 2-DOF 1T1R parallel mechanism with a redundant branch chain was designed.Its optimal actuation scheme was determined through comprehensive performance analysis.[Methods]Firstly,a PR-constrained branch chain was added to the center of the moving platform of the 3-DOF 2T1R planar six-bar mechanism to constrain the one-dimensional translation of the moving platform,and a 3-limb 2-DOF 1T1R symmetrical parallel mechanism with one redundant branch chain was obtained.Then,two driving pairs of the mechanism have two different methods on three branch chains.To further investigate the impact of different selection schemes for driving pairs on the performance of the mechanism,systematic calculations,in-depth analysis,and comprehensive comparisons were conducted on the topological,kinematic,dynamic,and stiffness properties of the mechanism under the two driving schemes.[Results]The analysis results show that the driver scheme selection rules based on performance adaptation to application scenarios are effective.The study is helpful to further discuss the selection method of drive pair,the influence law and even the topology design method of the parallel mechanism with redundant branch chains.
Keywords：Redundant branch chainPlanar parallel mechanismTopology designActive joint selection
Publication Date：2026-04-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：10( 1-10 )