Analysis and optimum design of 2-DOF micro-positioning stage

A two-degree-of-freedom (2-DOF) micro-positioning stage driven by piezoelectric actuator (PZT) is developed and the simplified modeling of the micro-positioning stage is discussed. The x and y direction stiffness of the micro-positioning stage is deduced according to the theory of structural mechanics. After simplifying the micro-positioning stage as a 2-DOF spring-mass system, two resonant frequencies of the micro-positioning stage are derived. The comparative results of the theory, finite element analysis (FEA) and experiments show the accuracy of theory model and the validity of FEA. FEA on static and dynamic behavior of the micro-positioning stage is performed and FEA indicates that the stiffness, the natural frequency and the driving force will increase and the maximum stress of the stage will also increase, as the hinge length decreases or the hinge width increases. Modification of dimensions enables us to control and optimize natural frequency, displacement, stresses, and force to be applied to the hinges to achieve the desired response of the micro-positioning system. Finally, a simple optimum design procedure is developed by which the proper dimensions of the micro-positioning stage can be found.