Design, analysis and experiment of a novel ring vibratory gyroscope

This work presents the design, analysis, simulation and experiment of a novel ring vibratory gyroscope based on piezoelectric effect. The gyroscope has a simple millimeter-scale resonator which comprises of a metallic structure and eight piezoelectric elements. The piezoelectric elements attached to the metallic structure excite the primary mode of the resonator, sense the second mode caused by Coriolis force and output signal proportional to input angular velocity. A theoretical analysis on the proposed gyroscope is performed using the AMM method and DM method for the forced vibration solution of active mode and sense mode with the inclusion of the Coriolis force coupling. The sensitivity of the gyroscope and its dependence on some geometry parameters are obtained. The working principle is validated by using FEM simulation. The metallic structure of the prototypal gyroscope was machined by precision turning and electrical charge technologies, as a result, the adherence process of the piezoelectric elements is simplified and the positioning precision is improved, which ensures the high axial symmetry of the resonator. A prototypal gyroscope is selected for practical experiments. The natural frequencies of active mode and sense mode of the prototype are close, the frequency split is 0.06 Hz, and the quality factor is approximately 5000 in atmosphere. Therefore, the gyroscope can work properly without a vacuum package. A control circuit was specially designed to activate the resonator and readout the angular velocity signal. The performance of the gyroscope is characterized on a precision rate table. The experimentally obtained scale factor is 65.5 mV/degrees/s, the nonlinearity is 1323 ppm in range of +/- 150 degrees/s, the angle random walk is about 0.05 degrees/h(1/2), and the zero-bias instability is about 1.5 degrees/h at room temperature. There is a good linear relation between the sensing voltage and the angular velocity, suggesting that the novel ring vibratory gyroscope is a good candidate for low and medium rotation speed measurements. (C) 2011 Elsevier B.V. All rights reserved.