A new angular velocity sensor using the temperature stable AT-cut quartz

Abstract

The feasibility of a new angular velocity sensor using the temperature stable AT-cut quartz was presented. The sensor consisted of one pair of electrodes for driving the fundamental thickness shear mode, and another pair of electrodes for sensing the angular velocity. Two tines extended outward from resonator, and in the plane of the plate. The tines were designed to be sensitive to angular velocity of the resonator. The Coriolis body force caused by the cross product of the angular velocity with the linear momentum of the vibrating tines changes the their mode shapes that in turn perturbed the thickness shear mode, and changed the voltage at the sensing electrodes. A vibratory gyroscope with a trapped energy thickness mode as the main driving mode offers good improvements in terms of frequency stability and less dependence on the mounting supports and lead installation of the sensing element. Since the AT-cut resonators were known to have good f-T curves and long term aging, such a gyroscope would have the advantages of a stable quartz AT-cut resonator. Results for two angular velocity sensors were presented: (1) a 5 MHz sensor with a sensitivity of 5.8 mV/deg./s angular velocity about the X-axis, and (2) a 37 MHz sensor with a sensitivity of 0.38 mV/deg./s angular velocity about the Z-axis.