The research on orientation capability of the Stewart-Gough manipulator

This paper mainly addresses the orientation-singularity and orientation capability analyses of the Stewart-Gough manipulator. Based on a particular kind of orientation representation of the manipulator, a polynomial expression of thirteen degree in the mobile platform orientation parameters is derived, which represents the orientation-singularity locus of the manipulator at a given position, and graphical representations of the orientation-singularity locus of the manipulator are given to illustrate the result. Then a new performance index which describes the orientation capability of the manipulator at a given position is presented. Furthermore, effects of the design parameters of the moving platform, including the central angle, the ratio of the moving platform to the base one and the position of the moving platform on the orientation capability of the manipulator are also presented in detail in this paper.