Microfluidic Gyroscope Drive And Detection Technology

Micromachined thermal gas gyroscope (MTGG) uses gaseous medium instead of mechanical proof mass as sensing element. MTGG takes advantages of simple configuration, large working range and high shock resistance. MTGG can be widely used in the field of military and civilian.The design and experiment about the detecting & controlling circuits of MTGG are introduced in this paper. The scheme of MTGG including driving and detecting is introduced first, and the detecting & controlling circuits of MTGG based on the phase sensitive detector are designed. Then, the design of digital MTGG which includes digital interface and digital detecting & controlling circuits is introduced. The main functions of the digital interface are as follows:the output signal of the analog circuit is transferred into digital signal by the A/D convert circuit, the temperature of MTGG is measured, the digital filiter and temperature compensation are realized by the microcontroller, and the digital voltage is finally output by the serial interface inside the microcontroller. A digital detecting & controlling circuits is designed, in which the A/D convert circuit is directly applied after the output of the difference amplifier of gyroscope sensitive unit, the digital phase sensitive detector is designed based on microcontroller system and the drive and reference signals are generated by the Timer of the microcontroller. Digital detecting & controlling circuits can not only reduce the noise sources introduced by analog components but also take advantages of the miniaturization and integration of digital circuit. In the end, the MTGG prototype based on analog circuit and the MTGG prototype with digital interface and the MTGG prototype based on digital detecting & controlling circuits are respectively tested.The measurement results of the MTGG prototype based on analog circuit show a threshold and resolution of 1°/s, a zero-bias stability of 3.873°/s, a system scale of±1200°/s, and a shock resistance of 20,000g. The measurement results of the MTGG prototype with digital interface show a threshold and resolution of 1°/s, and a zero-bias stability of 2.161°/s. Through the temperature compensation, the drift rate temperature sensitivity of MTGG is reduced from 0.285°/s/℃to 0.093°/s/℃which is reduced by 66.3%. The measurement results of the MTGG prototype based on digital detecting & controlling circuits show a threshold and resolution of 1°/s, and a zero-bias stability of 1.061°/s. The experiments prove the validity of the deigsned circuits.