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A vibrating structure gyroscope, standardised by IEEE as Coriolis vibratory gyroscope (CVG),〔IEEE Std 1431–2004 Coriolis Vibratory Gyroscopes.〕 is a wide group of gyroscope using solid-state resonators of different shapes that functions much like the halteres of an insect. The underlying physical principle is that a vibrating object tends to continue vibrating in the same plane as its support rotates. In the engineering literature, this type of device is also known as a ''Coriolis vibratory gyro'' because as the plane of oscillation is rotated, the response detected by the transducer results from the Coriolis term in its equations of motion ("Coriolis force"). Vibrating structure gyroscopes are simpler and cheaper than conventional rotating gyroscopes of similar accuracy. Miniature devices using this principle are a relatively inexpensive type of attitude indicator. ==Theory of operation== Consider two proof masses vibrating in plane (as in the MEMS gyro) at frequency . Recall that the Coriolis effect induces an acceleration on the proof masses equal to , where is a velocity and is an angular rate of rotation. The in-plane velocity of the proof masses is given by: , if the in-plane position is given by . The out-of-plane motion , induced by rotation, is given by: : is a spring constant in the out of plane direction, : is a magnitude of a rotation vector in the plane of and perpendicular to the driven proof mass motion. In application to axi-symmetric thin-walled structures like beams and shells, Coriolis forces cause a precession of vibration patterns around the axis of rotation. For such shells, it causes a slow precession of a standing wave around this axis, with an angular rate that differs from input one. This is the ''wave inertia effect'', discovered in 1890 by British scientist George Hartley Bryan (1864–1928).〔Bryan G.H. On the Beats in the Vibrations of a Revolving Cylinder or Bell ''//Proc. of Cambridge Phil. Soc. 1890, Nov. 24. Vol.VII. Pt.III. - P.101-111.''〕 If we consider a polarization of a shear (transverse) elastic wave propagating along an acoustic axis in a solid—a polarization rotation effect from rotation of the body as a whole (the ''polarization inertia effect'') can be observed too. (It was noted by Ukrainian scientist Sergii A. Sarapuloff in the early 1980s,〔Sarapuloff S.A. General Solution of Problem of Elasticity Theory of a Rotated Medium ''//Mechanics of Gyroscopic Systems. Issue 8. – Kyiv. 1989. – P.57-61.'' (''In Russian''.)〕 It also produces a corresponding modification of Green-Christoffel's tensors in acoustics〔Sarapuloff S.A., and Ulitko I.A. Rotation Influence upon Bulk Waves in an Elastic Medium and their Usage in Solid-State Gyroscopy ''// VIII International Conference on Integrated Navigation Systems. – St. Petersburg. St.-Petersburg. The State Research Center of Russia - Central Scientific & Research Institute "ElektroPribor". RF. 2001. – P.127-129.〕〔Sarapuloff S.A. Polarization Precession Effects for Shear Elastic Waves in Rotated Solids //Proceedings of the 23rd KSNVE (Korean Society for Noise & Vibration Engineering) Annual Spring Conference. Yeosu-city, 24–26 April 2013. – P.842-848.''〕). 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「vibrating structure gyroscope」の詳細全文を読む スポンサード リンク
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