Decoupling Control of Micromachined Spinning-Rotor Gyroscope with Electrostatic Suspension

• Main Authors: Boqian Sun, Shunyue Wang, Haixia Li, Xiaoxia He
• Format: Article
• Language: English
• Published: MDPI AG 2016-10-01
• Series: Sensors
• Subjects: decoupling control; gyroscope rebalance loop; stiffness compensation; inner-loop decoupling compensator; outer-loop decoupling compensator; micromachined spinning-rotor gyroscope; electrostatic suspension
• Online Access: http://www.mdpi.com/1424-8220/16/10/1747

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.