Design and analysis of a 3-RPRS modular parallel manipulator for rapid deployment

In this paper, the design of a new 6-DOF, 3RPRS parallel manipulator has been proposed. Different from the conventional Stewart-Gough platform manipulator which has six extensible legs, the 3RPRS parallel manipulator employs three identical RPRS legs to support the moving platform. Consequently, it possesses a compromised performance (e.g., workspace, accuracy and stiffness) between a serial robot and a six-legged fully parallel manipulator. Since all the joint axes, excluding the three spherical joints at the leg-ends, are parallel to each other and perpendicular to the base plane, the 3RPRS parallel manipulator presents a promising platform structure with simple kinematics. A two-dimensional projection approach is proposed for the displacement and singularity analysis. For rapid deployment, the modular design methodology is employed, which is able to reduce the complexity of the overall design problem to a manageable level.