Analytic singularity equation and analysis of six-DOF parallel manipulators using local structurization method

An analytic expression for the singularities of six-degree of freedom Stewa rt-platform type parallel manipulator (six-DOF SPM) is obtained using the c oncept of local structurization method (LSM) with extra sensors. The result ing equation, however, does not include sensor values. It is only a functio n of design variables. The equation is basically a third-degree polynomial and it exactly provides singularity information of general SPM's, Several s ymbolic examples are shown to verify the exactness of the singularity equat ion by comparing it with previously reported singularities. Some other nume rical examples are also shown using the proposed singularity equation.