Design of flexure hinges in an H-drive precision stage with a large span

In order to balance the high translation stiffness and low twist stiffness in an H-drive precision stage with a large span, a design method based on flexure hinges combination is proposed. Firstly, various stiffness requirements in different degrees of freedom (DOF) of an H-drive precision stage with a large span are analyzed. Secondly, half-cartwheel flexure hinges combination is applied to balance these stiffness requirements. Thirdly, based on the Timoshenko beam theory, stiffness matrices of a single flexure hinge and combined hinges are established. Then, various structural parameters of the flexure hinge are determined by analyzing their influence on two performance indicators, including stiffness and motion precision. After that, finite element method is applied to verify these theoretical results. Finally, a stiffness identification experiment and a modal analysis experiment are conducted to test the 2-DOF stiffness of a single half-cartwheel flexure hinge and the natural frequency of the H-drive precision stage. The maximum error of stiffness between theoretical, simulation and experimental results is 13.4%. The natural frequency is up to 176.563 Hz, which could satisfy the control bandwidth requirement of the H-drive precision stage.