Surface acoustic wave gyroscope

Research Project

Project/Area Number	07555424
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	展開研究
Research Field	計測・制御工学
Research Institution	UNIVERSITY OF TOKYO
Principal Investigator	HIGUCHI Toshiro UNIVERSITY OF TOKYO Graduate School of Engineering, Department of Precision Machinery Eng.Professor, 工学系研究科, 教授 (10111569)
Co-Investigator(Kenkyū-buntansha)	TAKAHASHI Ayumu Sumitomo Precision Products CO., LTD.Business Planning & Development Dept.Assist, 商品開発部, 副参事 KUROSAWA Minoru University of Tokyo, Graduate School of Engineering, Department of Precision Mac, 工学系研究科, 助教授 (70170090)
Project Period (FY)	1995 – 1997
Project Status	Completed (Fiscal Year 1997)
Budget Amount *help	¥4,300,000 (Direct Cost: ¥4,300,000) Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1996: ¥3,600,000 (Direct Cost: ¥3,600,000)
Keywords	gyro sensor / micro sensor / surface acoustic wave / Rayleigh wave / lithium niobate / piezoelectric sensor / electro mechanical transducer / piezoelectric transducer / 弾性表面波 / 圧電トランスジューサ / ニオブ直交リチウム / マイクロマシニング / ジャイロスコープ / 振動ジャイロ / 圧電基板 / IDT / 超音波
Research Abstract	A surface acoustic wave gyroscope using an operation frequency of 15 MHz, a wave mode of Rayleigh wave and a piezoelectric substrate of LiNbO3 128ﾟ Y-cut was designed. Electrodes of an interdigital transducer (IDT : called "generator IDT") and two reflectors are aligned for generating a standing wave on the surface. Two IDTs (called "sensor IDTs") and two reflectors for receiving a secondary wave are aligned perpendicularly into the electrodes which generate the primary standing wave. Perturbation electrodes are arranged between the IDTs. A principle of this gyroscope is receiving the secondary wave excited by the perturbation electrodes with rotation of the substrate. An output voltage of few tens of mV with rotation rate 2pi rad/s was estimated by using equivalent circuit models. This sensor with electrodes of aluminum and chromium and the size of 25mm x 45mm was fabricated by using photo-process. On sensor IDT,a different anti-resonance frequency from a resonance frequency of generator IDT and low Q factor was found from measuring admittance characteristic versus frequency. Therefor, output voltage will be decreased to less than one hundred muV.And waves scattered by the perturbation electrodes were observed. These scattered waves were detected by the sensor IDTs. Some perturbation electrode with different vibration condition from our design were found by vibration measuring. Further, the primary standing wave was not formed clearly. Thus, a vibrating table was used to detect the output of the gyroscope, for the output voltage was too low. The output of sensor IDT was amplified with locking in the frequency of table vibration. But, unfortunately, the output voltage could not detected yet.