Sun Jiangkun, Yu Sheng, Zhang Yongmeng, Li Qingsong, Xi Xiang, Lu Kun, Wu Xuezhong, Xiao Dingbang
National University of Defense Technology, Changsha, 410073 China.
Microsyst Nanoeng. 2021 Oct 13;7:79. doi: 10.1038/s41378-021-00306-6. eCollection 2021.
Whole-angle gyroscopes have broad prospects for development with inherent advantages of excellent scale factor, wide bandwidth and measurement range, which are restrictions on rate gyroscopes. Previous studies on the whole-angle mode are based mostly on the linear model of Lynch, and the essential nonlinearity of capacitive displacement detection is always neglected, which has significant negative effects on the performance. In this paper, a novel real-time calibration method of capacitive displacement detection is proposed to eliminate these nonlinear effects. This novel method innovatively takes advantage of the relationship between the first and third harmonic components of detective signals for calibration. Based on this method, the real-time calibration of capacitive displacement detection is achieved and solves the problems of traditional methods, which are usually related to the vibration amplitude, environmental variations and other factors. Furthermore, this novel calibration method is embedded into a whole-angle control system to restore the linear capacitive response in real time and then combined with a microshell resonator for the first time to exploit the enormous potential of an ultrahigh factor and symmetric structure. The effectiveness is proven because the angle drift is reduced significantly to improve the scale-factor nonlinearity by 14 times to 0.79 ppm with 0.0673°/h bias instability and a 0.001°/s rate threshold, which is the best reported performance of the MEMS whole-angle gyroscope thus far. More importantly, this novel calibration method can be applied for all kinds of resonators with the requirement of a linear capacitive response even under a large resonant amplitude.
全角度陀螺仪具有优异的比例因子、宽带宽和测量范围等固有优势，在发展方面具有广阔前景，而这些正是速率陀螺仪所受限的方面。以往对全角度模式的研究大多基于林奇的线性模型，电容式位移检测中固有的非线性一直被忽视，这对性能有显著负面影响。本文提出一种新颖的电容式位移检测实时校准方法，以消除这些非线性效应。这种新方法创新性地利用检测信号的一次和三次谐波分量之间的关系进行校准。基于该方法，实现了电容式位移检测的实时校准，解决了传统方法通常与振动幅度、环境变化等因素相关的问题。此外，这种新颖的校准方法被嵌入到全角度控制系统中，实时恢复线性电容响应，然后首次与微壳谐振器相结合，以发挥超高品质因数和对称结构的巨大潜力。其有效性得到了证明，因为角度漂移显著降低，比例因子非线性改善了14倍，达到0.79 ppm，偏置不稳定性为0.0673°/h，速率阈值为0.001°/s，这是迄今为止MEMS全角度陀螺仪报道的最佳性能。更重要的是，这种新颖的校准方法可应用于所有需要线性电容响应的谐振器，即使在较大谐振幅度下也是如此。
