Dexterous Workspace Optimization for a New Hybrid Parallel Robot Manipulator

In this paper, a new hybrid parallel robot (HPR) manipulator is introduced. First three kinematic limbs of six-legged general Stewart plafform (6DOF GSP) manipulator are disconnected. Afterward, each passive universal joint of remaining three-legged parallel manipulator (three-UPS) is mounted at the center of each second passive revolute joint of RPR planar parallel manipulator (3DOF PPM) where underlined letters present active joints. Active actuators of PPM mounted between base platform of GSP and ground perform translations along x and y-axes, and rotation about z-axis. Remaining three limbs of GSP mechanism provide translation z-axis, and rotation about x- and y-axes only. Thus HPR can perform motion with full dimensions (translation and rotation about x-, y-, and z-axes). Optimizations are performed by using particle swarm optimization algorithm. Optimization results demonstrated that HPR provides better dexterity and singularity-free workspace characteristics than GSP.