Static balancing and dynamic modeling of a three-degree-of-freedom parallel kinematic manipulator

This research is concerned with the design and analysis of a parallel kinematic manipulator (PKM) with three degrees of freedom (DOF). The proposed PKM combining the spatial rotational and translational degrees of freedom has varied advantages and good potential applications of materials handling. First, the static balancing of the parallel manipulator is investigated. The definition and methodology of static balancing are introduced. Two methods including adjusting kinematic parameters and counterweights are applied to the structure and the counterweights method leads to static balancing of the PKM. The conditions of static balancing are given. Then the dynamic model of the proposed PKM is deduced. It describes the relationship between the driving forces and the motion of the end-effector platform. Two approaches, the Newton-Euler and the Lagrange methods, are compared and the later one is selected to build the dynamic model of the 3-DOF tripod mechanism.