Title :
Suppression of null signals in LiTaO3 crystal fork vibratory gyroscope
Author :
Wakatsuki, Noboru ; Ono, Masaaki ; Yamada, Sumio ; Kikuchi, Kazuro ; Yamauchi, Motoi
Author_Institution :
Ishinomaki Senshu Univ., Ishinimaki, Japan
Abstract :
A LiTaO3 tuning fork vibratory gyroscope has a high sensitivity, because of its high electromechanical coupling for the bending fx mode and its orthogonal fx mode, and high Q value for driving and adjustable Q value for detecting fy mode. Our trial LiTaO3 fork with cuboid arms (7.0 mm long, 1.0 mm wide, 1.0 mm thick, 0.3 mm gap) has a high sensitivity of 0.5 mV/deg/sec for 1 V pp input at 16.5 KHz. But the sensitivity is often reduced by spurious driving and detection modes coupling due to electrostatic coupling, electromechanical coupling and mechanical coupling. We experimentally analyzed the leakage couplings separately and proposed a new configuration of driving and detection electrodes for functional laser trimming. Also we proposed the additional slit formed by laser at an arm-edge of fork to achieve orthogonal vibrations for the fx mode and the fy mode. These functional YAG laser trimmings can suppress the leakage coupling or leakage signal voltage to -50 dB of driving voltage
Keywords :
crystal resonators; electromechanical effects; gyroscopes; laser beam machining; lithium compounds; 16.5 kHz; LiTaO3; Q value; bending fx mode; crystal fork vibratory gyroscope; cuboid arms; electromechanical coupling; electrostatic coupling; fy mode; functional laser trimming; leakage signal voltage; mechanical coupling; null signals; orthogonal fx mode; orthogonal vibrations; sensitivity; spurious detection modes; spurious driving modes; Arm; Electrodes; Electrostatics; Gyroscopes; Laser modes; Laser tuning; Leak detection; Optical coupling; Vibrations; Voltage;
Conference_Titel :
Ultrasonics Symposium, 1995. Proceedings., 1995 IEEE
Conference_Location :
Seattle, WA
Print_ISBN :
0-7803-2940-6
DOI :
10.1109/ULTSYM.1995.495613