Abstract: In order to solve the conflict between large stroke and high precision of micro positioning platform, a novel 3-DOF complaint parallel mechanism is proposed. The three chains connect to the platform with a special way, which makes the mechanism behave a compact structure and good mechanical properties. At the same time, the mechanism uses electromagnetic actuators that are characterized by large stroke, high precision and easy to control as the driving component, which guarantees the requirement of large stroke and high resolution of the mechanism without a need for amplifier mechanisms. Wide-range flexure hinges are used to replace the common spherical joints, which will reduce the difficulty of processing and manufacturing of the complaint mechanism, as well as the stiffness modeling. The kinematic characteristics of the proposed 3-P(4S) parallel mechanism is analyzed by using the screw theory. Combined with unit stiffness matrix method and matrix displacement method, the static stiffness model of the mechanism is obtained. ANSYS analysis is made to verify the accuracy of the stiffness model.

Key words: Compliant mechanism, Screw theory, Stiffness model