Inherently robust micromachined gyroscopes with 2-DOF sense-mode oscillator
Inherently robust micromachined gyroscopes with 2-DOF sense-mode oscillator
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DOI：
10.1109/jmems.2006.872224
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发表时间：
2006-04-01
影响因子：
2.7
通讯作者：
Shkel, AM
中科院分区：
文献类型：
--
作者：
Acar, C;Shkel, AM
用于大批量应用的可靠的振动微机械陀螺仪的商业化已被证明是极具挑战性的，主要是由于动力系统对制造和环境变化的响应的高灵敏度。本文报道了一种新型的微机械陀螺仪与两个自由度（DOF）的敏感模式振荡器，提供固有的鲁棒性对结构参数的变化。2-DOF感测模式振荡器提供具有两个谐振峰和峰之间的平坦区域的频率响应，而不是如常规陀螺仪中的单个谐振峰。该器件标称工作在感测模式响应曲线的平坦区域，其中响应的幅度和相位对参数波动不敏感。此外，通过利用2自由度传感模式振荡器中的振荡的动态放大来提高灵敏度。因此，仅通过机械系统设计就实现了对温度、阻尼和结构参数变化的改进的鲁棒性。原型陀螺仪制造使用体微加工工艺，和设备的性能和鲁棒性进行了实验评估。在25 V直流偏置和3 V交流驱动信号导致5.8 pm驱动模式振幅的情况下，陀螺仪在大气压力下在50 Hz带宽上表现出0.64 degrees/s/root Hz的实测本底噪声。在平坦的工作区域的传感模式响应也被实验证明是固有的压力，温度和直流偏置变化不敏感。
Commercialization of reliable vibratory micromachined gyroscopes for high-volume applications has proven to be extremely challenging, primarily due to the high sensitivity of the dynamical system response to fabrication and environmental variations. This paper reports a novel micromachined gyroscope with two degrees-of-freedom (DOF) sense-mode oscillator that provides inherent robustness against structural parameter variations. The 2-DOF sense-mode oscillator provides a frequency response with two resonant peaks and a flat region between the peaks, instead of a single resonance peak as in conventional gyroscopes. The device is nominally operated in the flat region of the sense-mode response curve, where the amplitude and phase of the response are insensitive to parameter fluctuations. Furthermore, the sensitivity is improved by utilizing dynamical amplification of oscillations in the 2-DOF sense-mode oscillator. Thus, improved robustness to variations in temperature, damping, and structural parameters is achieved, solely by the mechanical system design. Prototype gyroscopes were fabricated using a bulk-micromachining process, and the performance and robustness of the devices have been experimentally evaluated. With a 25 V dc bias and 3 V ac drive signal resulting in 5.8 pm drive-mode amplitude, the gyroscope exhibited a measured noise-floor of 0.64 degrees/s/root Hz over 50 Hz bandwidth in atmospheric pressure. The sense-mode response in the flat operating region was also experimentally demonstrated to be inherently insensitive to pressure, temperature, and dc bias variations.