Singularity Analysis of Indigenously Developed 6-dof Sps Parallel Manipulator in Its Calculated Workspace

Striving for greater accuracy and greater performance, some machine manufactures are developing parallel structure for the next generation machine. This necessarties that these machines need to be analyzed for the effects of existing singularities inside or boundary of evaluated workspace of indigenously developed 6-DoF SPS (S: Spherical, P: Prismatic) parallel manipulator here in Bhabha atomic research Centre, Mumbai. Singular configurations are particular poses of the moving platform of manipulator, in which the parallel manipulator becomes uncontrollable and must therefore be prevented during operation. This paper addresses nominal kinematic model and existing singularities in its calculated workspace of selected configuration of 6DoF fully parallel manipulators. Starting from the inverse nominal kinematic model of parallel manipulator, a Matlab code was written to solve the inverse kinematic model for workspace evaluation of 6-DoF parallel manipulator. Then after inverse Jacobian matrix, which maps the moving platform’s position and orientation to the actuated joint velocities are derived. The singularity analysis is transformed into a search for specific geometric conditions inside or boundary of the evaluated workspace, which apply, when the manipulator is in a singular pose. In this paper the checking of singularities has been done within and boundary of usable workspace with the help of determinant of Jacobian matrix. Usable workspace is the subset of total evaluated workspace which is defined by the application of the manipulator system. Furthermore it has been found out that there is no any singularities existing within or in boundary of usable workspace of this selected configuration of 6-DoF SPS parallel manipulator system.