Effect of polarized electric field on piezoelectric cylinder vibratory gyroscope

The effects of the resonant frequency of the drive and sense modes and the mechanical quality factor (Q) of vibratory gyroscopes have been investigated in many research papers. In this article, in addition to these factors, the effect of polarized electric field on the sensitivity of a piezoelectric cylinder-type vibratory gyroscope is discussed. We derive a relation for the sensitivity for the gyroscope using the Coriolis effect, the material properties of ceramics, and the applied polarized voltage, and find that the sensitivity is proportional to the polarized electric field. This study also looks at the influence of the geometry of the cylinder (diameter and length), and that of the electrodes (width and clearance) on the polarized electric field. From simulation using ANSYS models developed for six-electrode and eight-electrode cylinder gyroscopes, we conclude that diameter is a significant factor in determining the polarized electric field, and a large diameter requires a high polarized voltage for complete polarization. In addition, equal width of the electrode and equal clearance between neighboring electrodes yields a better polarized electric field. Also, the frequencies of the primary and secondary modes are seen to be nearly equal due to the axisymmetry of the cylinder gyroscope, which is an advantage of high sensitivity. The resonant frequency obtained from experiments on a ceramic cylinder gyroscope is a close approximation of the value calculated from the simulation models. There is a good linear relation between the sensing voltage and the rotation speed, suggesting that the piezoelectric ceramic cylinder gyroscope is a good candidate for low and medium rotation speed measurements. (c) 2006 Elsevier B.V. All rights reserved.