Design, modeling, and testing of a novel 6-DOF micropositioning stage with low profile and low parasitic motion

We developed a novel piezoelectrically actuated 6 degree-of-freedom (DOF) stage for micropositioning. To achieve a parallel mechanism with high stiffness, compact size, and low parasitic motion for 6-DOF positioning, an orthogonal actuator configuration is proposed and actuation units are carefully designed. For the purpose of suppressing parasitic motion in the overall stage, the ratios of the lateral stiffness to actuating directional stiffness of the actuation units are minimized under the condition that the stress at any point in the stage does not exceed the allowable strength. Flexure hinges and lever linkages are effectively applied to the horizontal and vertical actuation units. A physics-based model of the stage is developed to ensure low system order and high reliability. The model parameters are estimated by experiment and finite element analysis. Open-loop tests including sinusoidal and step responses verify low parasitic motion and reliability of the model. Closed-loop step responses with a model-based controller validate the high micropositioning performance of the stage.