title: Decoupling Control of Micromachined Spinning-Rotor Gyroscope with Electrostatic Suspension.
abstract: A micromachined gyroscope in which a high-speed spinning rotor is suspended electrostatically in a vacuum cavity usually functions as a dual-axis angular rate sensor. An inherent coupling error between the two sensing axes exists owing to the angular motion of the spinning rotor being controlled by a torque-rebalance loop. In this paper, a decoupling compensation method is proposed and investigated experimentally based on an electrostatically suspended micromachined gyroscope. In order to eliminate the negative spring effect inherent in the gyroscope dynamics, a stiffness compensation scheme was utilized in design of the decoupled rebalance loop to ensure loop stability and increase suspension stiffness. The experimental results show an overall stiffness increase of 30.3% after compensation. A decoupling method comprised of inner- and outer-loop decoupling compensators is proposed to minimize the cross-axis coupling error. The inner-loop decoupling compensator aims to attenuate the angular position coupling. The experimental frequency response shows a position coupling attenuation by 14.36 dB at 1 Hz. Moreover, the cross-axis coupling between the two angular rate output signals can be attenuated theoretically from -56.2 dB down to -102 dB by further appending the outer-loop decoupling compensator. The proposed dual-loop decoupling compensation algorithm could be applied to other dual-axis spinning-rotor gyroscopes with various suspension solutions.
authors: Department of Precision Instrument, Tsinghua University, Beijing 100084, China. sbq12@mails.tsinghua.edu.cn.
authors: Boqian
authors: B
authors: Sun
authors: Department of Precision Instrument, Tsinghua University, Beijing 100084, China. wsy15@mails.tsinghua.edu.cn.
authors: Shunyue
authors: S
authors: Wang
authors: Department of Precision Instrument, Tsinghua University, Beijing 100084, China. li-hx03@mails.tsinghua.edu.cn.
authors: Haixia
authors: H
authors: Li
authors: Department of Precision Instrument, Tsinghua University, Beijing 100084, China. hexx@mail.tsinghua.edu.cn.
authors: Xiaoxia
authors: X
authors: He
keywords: decoupling control; electrostatic suspension; gyroscope rebalance loop; inner-loop decoupling compensator; micromachined spinning-rotor gyroscope; outer-loop decoupling compensator; stiffness compensation