DOI: 10.1063/5.0153518

Abstract

A tuning fork gyroscope (TFG) with orthogonal thin-walled round holes in the driving and sensing directions is proposed to improve sensitivity. The thin walls formed by through holes produce stress concentration, transforming the small displacement of tuning fork vibration into a large concentrated strain. When piezoelectric excitation or detection is carried out here, the driving vibration displacement and detection output voltage can be increased, thereby improving sensitivity. Besides, quadrature coupling can be suppressed because the orthogonal holes make the optimal excitation and detection positions in different planes. The finite element method is used to verify the benefits of the holes, and the parameters are optimized for better performance. The experimental results show that the sensitivity of the prototype gyroscope with a driving frequency of 890.68 Hz is 100.32 mV/(°/s) under open-loop driving and detection, and the rotation rate can be resolved at least 0.016 (°/s)/√Hz, which is about 6.7 times better than that of the conventional TFG. In addition, the quadrature error is reduced by 2.7 times. The gyroscope has a simple structure, high reliability, and effectively improves sensitivity, which is helpful to guide the optimization of piezoelectric gyroscopes and derived MEMS gyroscopes

文章摘要

为了提高音叉陀螺仪的灵敏度，提出了一种在驱动方向和传感方向上带有正交薄壁圆孔的音叉陀螺仪。通孔形成的薄壁产生应力集中，将音叉振动的小位移转化为较大的集中应变。当在此处进行压电激励或检测时，可以增加驱动振动位移和检测输出电压，从而提高灵敏度。此外，正交孔使得最佳激励和检测位置位于不同平面上，可以有效抑制正交耦合。采用有限元方法验证了孔的作用，并对参数进行了优化，以获得更好的性能。实验结果表明，驱动频率为890.68 Hz的原型陀螺仪在开环驱动和检测下的灵敏度为100.32 mV/°/s，转速分辨率至少为0.016 (°/s)/Hz，比传统TFG提高约6.7倍。此外，正交误差减小了2.7倍。该陀螺仪结构简单，可靠性高，有效提高了灵敏度，有助于指导压电陀螺仪和衍生MEMS陀螺仪的优化设计。

图片摘要

设计了d = 4.6 mm的改进TFG与传统TFG进行比较。在20 s的连续测量周期内，分别逆时针、顺时针施加1.25、2.5、5°/s的旋转速率，得到两个陀螺仪对应的时间响应，如图(a)所示。可以清楚地观察到，改进后的TFG的灵敏度远高于传统的TFG，并且传统的TFG已经很难区分1.25°/s的旋转速率。根据响应数据发现，两种TFG的噪声水平也比较接近，改进TFG和常规TFG的噪声水平分别为37 mVpp和33 mVpp。最后，在±6.25°/s范围内测量比例因子，结果如图(b)所示。改进后的TFG和传统TFG的比例因子分别为100.32 mV/(°/s)和13.44 mV/(°/s)，灵敏度提高了约7.5倍。改进TFG和常规TFG的最小旋转速率分别为0.016(°/s)/Hz和0.107(°/s)/Hz，分辨率提高了6.7倍。

亮点：

带有正交薄壁孔的改进音叉陀螺仪(TFG)通过局部应力集中提高灵敏度，且由于最优驱动位置和传感位置的非共面性，有效地抑制正交耦合。实验结果表明，改性TFG的灵敏度提高了7.5，分辨率提高6.7倍，正交误差减小了2.7。