A Slot-Structure MEMS Gyroscope Working at Atmosphere with Tunable Electrostatic Spring Constant

作者：Hu, Shichang^*; Jin, Zhonghe; Zhu, Huijie; Wang, Hao; Ma, Mingjun

来源：Journal of Microelectromechanical Systems, 2013, 22(4): 909-918.

DOI：10.1109/JMEMS.2013.2250485

• Electrostatic spring constant
• microelectromechanical systems (MEMS) gyroscope
• mode matching
• slot-structure
• triangular electrode
• variable-area capacitor

This paper proposed a novel slot-structure z-axis gyroscope with a positive or negative electrostatic spring. The slot-structure gyroscope has in-plane drive and sense modes. Different from conventional comb finger structure, variable-area fixed out-of-plane electrodes under the proof-mass are used to excite the in-plane vibratory modes. To overcome the disadvantage that the resonant frequencies are unable to be adjusted through variable-area capacitors in the conventional slot-structure gyroscope, a variable-area capacitor with triangular shape fixed electrodes is designed to introduce the electrostatic tuning of the in-plane vibratory modes. A voltage difference V-t across the triangular fixed electrodes and movable electrodes produces a positive or negative electrostatic spring. The induced electrostatic spring constant is proportional to V-t(2). A prototype with a positive electrostatic spring is fabricated and tested. The difference of the nature frequencies of the drive mode and sense mode is about 13.5 Hz. A 15 V V-t makes the gyroscope perfect mode matching. The scale factor of the prototype is about 72mV/degrees/s when V-t is 0 V and increases with V-t. It presents a scale factor of 320.6mV/degrees/s and noise density of 11.63 degrees/h/vHz when mode matched. Interestingly, the bandwidth of the gyroscope only slightly decreased from the initial value of 7 Hz to 4.6 Hz when mode matched, possible reasons are discussed in this paper. [2011-0297]

• 出版日期2013-8
• 单位浙江大学