CLOSED-FORM DIRECT KINEMATICS SOLUTION OF A NEW PARALLEL MINIMANIPULATOR

Closed-form direct kinematics solution of a new three-limbed six-degre e-of-freedom minimanipulator is presented. Five-bar linkages and inext ensible limbs are used in synthesis of the minimanipulator to improve its positional resolution and stiffness. AN of the minimanipulator act uators are base-mounted. Kinematic inversion is used to reduce the dir ect kinematics of the minimanipulator to an eighth-degree polynomial i n the square of tangent of half-angle between one of the limbs and the moving platform. Hence, the maximum number of assembly configurations for the minimanipulator is sixteen. Furthermore, if is proved that th e sixteen solutions are eight pairs of reflected configurations with r espect to the plane passing through the lower ends of the three limbs. A numerical example is also presented and the results are verified by an inverse kinematics analysis.