Design modeling and simulation of a triple-axis MEMS gyroscope

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Design modeling and simulation of a triple-axis MEMS gyroscope

Zhang, Tingkai / Wei, Wang

In this paper a 3-axis gyroscope is presented. This gyroscope measures angular rate along three orthogonal directions when vibrating in its driving mode. The gyroscope has four masses sensing angular rate in plane(include x- and y-axis) and eight masses sensing angular rate along z-axis(perpendicular to plane). The four masses performing in plane sensing are linked together by four beams and are linked to the other eight masses for z-axis sensing by H-shape folded beams. The whole structure is fixed on glass substrate by suspending beams. When driven by electrostatic force the four masses for in plane sensing vibrate in plane. Two masses vibrate along x-axis and the other two masses vibrate along y-axis. Then the eight masses for z-axis sensing are driven vibrating with the four masses by the H-shape beams. When there is angular rate along x- or y-axis the two masses along y- or x-axis are driven vibrating in direction of z-axis by Coriolis force. And when there is angular rate along z-axis, the eight masses are driven vibrating in plane. By detecting the amplitude of the Coriolis induced motion of the masses, the rotation can be obtained. The structure of the gyroscope is modeled by finite element method(FEM). Based on the FEM model frequency matching and the dynamic behavior of the gyroscope are analyzed. The resonant frequency of the gyroscope is designed at about 13 kHz. On the basis of the final designed structure, the frequency's character under Coriolis effect is studied, the response for different rotation rate in all axes is presented, and finally the establishment character is analyzed.