A comparison study of two 3-DOF parallel manipulators: one with three and the other with four supporting legs

This paper presents a comparison study of the well-conditioned workspace and stiffness properties of two 3-degree-of-freedom (DOF) parallel manipulators, one with three supporting limbs and the other with four supporting limbs. The inverse kinematics and Jacobian of these two mechanisms are analyzed. The well-conditioned workspace of each mechanism is maximized and the stiffness properties are determined. A comparison of the results indicates that the Tricept manipulator out performs the 3-UPU parallel manipulator.