压电式微固体模态陀螺振子通过交变电压激振、传感电极感应出电荷。当激励电压频率为某阶振动模态谐振频率时, 感应电荷达到最大值。设计了谐振频率自动跟踪电路, 使陀螺稳定工作在谐振模态。使用现场可编程门阵列(FPGA)控制直接数字频率合成器(DDS)产生频率精确可调的激励电压, 驱动陀螺振子振动。检测谐振点对应的激励电压和感应信号间的相位差, 作为反馈信号调节激励电压频率。实验结果表明, 当相位差锁定区域处在98.48°~100.27°时, 振子感应电极输出信号最大, 振子处于谐振状态, 实现了振子谐振频率的跟踪锁定。该系统可用于以谐振器为核心器件的振子工作模态锁定与跟踪。

The piezoelectric micromachined modal gyroscope oscillator vibrates under the excitation of alternating voltage, and the sensing electrode induces charge. When the excitation voltage frequency is a certain order vibration mode resonance frequency, the induced charge reaches a maximum value. The resonant frequency automatic tracking circuit was designed to keep the gyro work stably in the resonant mode. Using fieldprogrammable gate array (FPGA) to control direct digital synthesizer (DDS) to generate the excitation voltage with precisely adjustable frequency. The phase difference between the excitation voltage and the induced signal was detected to act as the feedback signal to adjust the excitation voltage frequency. The results show that when the phase locking region locates 98.48°~100.27°, the induced voltage amplitude reaches the maximum value, the vibrator works in resonance state, thus the circuit realizes the tracking and locking of the vibrator resonance frequency. The system can be used for operation mode locking and tracking of the vibrators with resonator as the core device.