Abstract: Since the dynamic characteristics of existing micro motion stage based on flexible hinge apt to be influenced by material properties, designing and manufacturing errors, it is difficult to meet the high demands of dynamic response for the precision micro motion (especially frequency variable operation). A new method is proposed to design the dynamic characteristics adjustable micro motion stage based on tension stiffening effect. In the procedure, formulas of the equivalent stiffness and mass of the one end clamped and one end guided beam under preload are deduced, and the discrete-continuous optimization model of the number of spring leaf type flexure hinge groups(discrete variables) and cross-section size(continuous variables) is established based on the assumption of symmetric layout, by release the payload stiffness constraint, the model is transformed to the analytic solution series of cross-section size with the function of the number of spring leaf type flexure hinge groups. The payload stiffness and frequency adjustment range of different number of spring leaf type of flexure hinge groups at a given preload are analyzed, and the number of spring leaf type flexure hinge groups is determined by the demands of payload stiffness and frequency adjustment range. Application cases show the accuracy and the effectiveness of the presented method. Compared with finite element analysis, the relative error is less than 2%, realizing the optimal design of micro motion stage at given working stiffness, frequency and payload stiffness. The proposed method achieves a wide adjustment range of the stiffness and frequency, not only reduces the machining precision requirements, but also provides an implementation of the intelligent micro motion stage with the dynamic characteristics adaptive matched.

Key words: complaint mechanism, flexible hinge, intelligent motion stage, micro motion stage, tension stiffening