Research on spherical mapping method and application in crank design of spatial four-bar RSSR mechanisms
LIU Hui
XIE Jinghua
TANG Jun
ZHONG Lingchong
LIU Xiping
WANG Delun
Abstract：[Objective]To address the challenges in determining a unified and effective criterion for the crank existence conditions of spatial RSSR mechanisms,as well as the limited adaptability in engineering applications,a spherical mapping-based analytical method was proposed.[Methods]Firstly,by mapping the spatial RSSR mechanism onto the unit sphere,the crank existence conditions were discussed for the spherical image four-bar mechanism with equivalent variable link lengths.The crank existence conditions for the spatial RSSR mechanism were derived,thus forming a unified framework with the crank existence conditions of existing planar and spherical four-bar mechanisms.Secondly,fixing different components as the frame,the kinematic characteristics of the spatial RSSR mechanism were analyzed,thus demonstrating the correctness and effectiveness of the spherical mapping method for spatial RSSR crank design.Finally,using the installation structural parameters of a typical machine tool's ballbar measurement mechanism as an example,the kinematic characteristics of single-crank and double-crank spatial RSSR mechanisms were validated.[Results]The results demonstrate that the proposed method can effectively guide the parameter design of machine tool ballbar measurement mechanisms,thereby expanding new pathways for spatial mechanism theory and its applications.
Keywords：Spatial RSSR mechanismCrank existence conditionSpherical image mappingCrank
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：11( 21-31 )