Adaptive Input Estimation Methods for Improving the Bandwidth of Microgyroscopes

Unlike an accelerometer, the input to a vibratory microgyroscope is a product of the periodic excitation and the angular velocity to be detected. Consequently, the detection of the angular velocity requires a demodulation process involving a signal whose frequency is close to the resonance. Due to this special circumstance the dynamic performance characteristics such as the bandwidth of the microgyroscope sensors is severely limited. In this paper, we present adaptive input estimation methods to achieve wide bandwidth dynamic characteristics. Specifically, we present an adaptive estimator-based technique to estimate the angular motion by providing the Coriolis force as the input to the adaptive estimator. We present two methods, namely, the open-loop method and the closed-loop method. Both methods provide identical dynamic characteristics. But for the open-loop method, we require complete knowledge of all the parameters of the microgyroscopes whereas the closed-loop method can also be used where precise knowledge of the dynamic characteristics of the microgyroscopes is not available.