Design and analysis on micro-worktable using novel symmetric flexure hinge based on micro-assembly

Abstract

Micro-worktable is an important part of a micro-assembly system, and it implements the translation along X- and Y- axes and the rotation along X-, Y- and Z-axes of the assembly system. In order to amplify the micro-worktable displacement output and improve the micro-positioning accuracy, a novel 3-DOF organ-drive-inspecting micro-positioning worktable was designed and analyzed using modified double-parallelogram symmetrical structure flexure hinge and piezoelectric-actuators. For the symmetric mechanism effectively eliminated the coupling deflection angle and limited the vertical direction motion, the modified double-parallelogram flexure hinge increased the output displacement of X, Y and Z axes. Finite element model of the micro-worktable was established in ANSYS to make its static performances simulation by finite elements method (FEM). Simulation results showed that stiffness and accuracy of the modified double-parallelogram flexure hinge mechanism are higher than general double-parallelogram flexure hinge mechanism, and output displacement linearity is better than single-parallelogram flexure hinge mechanism. Flexure hinge mechanism and piezoelectric-actuator self-features reduce the system complexity, coupling displacement error, and also assure the stable accuracy, high resolution, and high frequent-response of the micro-positioning worktable. Finally, static performance was tested and analyzed through experiments. In experiments, the piezoelectric-power provided voltage to drive the micro-positioning worktable along X, Y and Z axes, and an electric inductance micrometer dial was used to measure the output displacement. Experimental results show that the resolution is 0.04μm for displacement in X, Y, and Z axes, and the maximum stroke length reaches 6μm. The design meets with the requirement of the micro-assembly system.