Design and analysis of a new three-axis micro-gyroscope

Abstract

A new three-axis micro-gyroscope which directly integrates spatial triaxial angular velocities sensitive function in single structure chip is designed and analyzed in the paper. The entire structure consists of three main parts: the left and right mechanism and middle mechanism. The middle mechanism with two top and down proof masses is connected with the left and right tuning fork mechanisms. Four proof masses are driven simultaneously to generate two orthogonal velocities in the planar for the sense of triaxial angular rates. The structural simulation of three-axis micro-gyroscope is implemented by the finite element method. The modal analysis results demonstrate that the new three-axis micro-gyroscope has the first mode of 24,719 Hz for synchronous drive of four proof masses, the second mode of 29,527 Hz for the z-axis angular velocity conversion, the sixth mode of 36,277 Hz for the x-axis angular velocity transformation, as well as the eighth mode of 38767 Hz for the y-axis angular velocity conversion respectively. The input-output simulation illustrates a mechanical sensitivity of 0.753 pm/deg/s for the x-axis angular velocity, a mechanical sensitivity of 0.332 pm/deg/s for the y-axis angular velocity and a mechanical sensitivity of 1.43 pm/deg/s for the z-axis angular velocity simultaneously, which verifies the sensitive characteristics of triaxial angular velocities. The simulation analysis of the mechanical coupling error indicates that the mechanical coupling error along y-axis (that is the sense direction of z-axis angular rates) has a maximum value of 103.3 deg/s. Moreover, the thermal analysis confirms the design of large frequency difference between drive mode and sense mode prominently suppresses the temperature influence on the mechanical sensitivity below 0.146% from −40 to 60 °C. The cross-axis coupling simulation shows that the new three-axis micro-gyroscope has a cross-axis coupling below 2.82%. The shock response results verify the new three-axis gyroscope has a shock resistance of 10,000 g in the presence of shock columns. In summary, the structure of the new three-axis gyroscope is proved to be feasible by the simulation and analysis.