Kinematic design of a novel 4-DOF parallel manipulator

A new four degrees-of-freedom (DOF) parallel manipulator that can produce 3-DOF translations and 1-DOF rotation (3T1R), has been proposed in this paper. It has two identical limbs connected to the moving platform through passive revolute joints, and each limb has two identical branches driven by a pair of base mounted collinear prismatic joints. Due to such a unique “4-2-1” kinematic structure, the 4-DOF parallel manipulator has the advantages of simple kinematics, large workspace, high speed, and high positioning accuracy. These advantages make it an appropriate candidate for high-speed and high-precision pick-and-place operations. To validate the proposed parallel manipulator design, mobility analysis is conducted based on the screw theory. Other critical design analysis issues, such as displacement, singularity, and workspace analyses, have been addressed in details.