文档介绍：Available online at hanism
and
Machine Theory
Mechanism and Machine Theory 43 (2008) 617–626
ate/mechmt
Extreme configuration bifurcation analysis and link safety
length of Stewart platform
Wei-Shan Chen, Hua Chen *, Jun-Kao Liu
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, PR China
Received 22 November 2006; received in revised form 12 March 2007; accepted 27 April 2007
Available online 19 June 2007
Abstract
The movement of parallel manipulator is carried out by controlling the length of links in usual condition. For a given
set of motion input parameters, the Stewart platform is possibly at the states of configuration bifurcation. In order that the
Stewart platform can move at will when the length of links changes in a determinate region, we discuss the problems about
the manipulator configuration and link length. The extreme configuration is presented based on the idea of analyzing the
movement state of parallel manipulator in link space. Sixteen kinds of extreme configurations for Stewart platform are
described with the vector expressions of link lengths. In order to avoid configuration bifurcations, the bifurcation charac-
teristics of extreme configurations are analyzed by homotopy method and static bifurcation condition. The safety length of
links is solved, which makes the manipulator work safely in the safety