Capacitive silicon micromachined gyro with mechanical coupling for sensitive signal reading 3

The actual mechanical coupling exists in the following aspects:

1. The center of mass G deviates from the coordinate origin, causing the vibration direction to deviate from the driving force direction, which means that the driving vibration will produce a component in the sensitive direction.

2. The dimensional machining errors of the supporting beam and comb teeth can result in stiffness coupling, stiffness asymmetry, driving force asymmetry, and displacement detection asymmetry.

3. Due to gas damping and structural asymmetry, damping coupling errors occur.  diode

For a line vibration capacitive silicon micro gyroscope, the driving voltage in the X direction will cause three modes of vibration: the driving mode, which is the line vibration of the sensitive mass along the X direction; Detecting mode, the vibration mode is the line vibration of the sensitive mass along the Y direction; Rotation mode, the vibration mode is the angular vibration of the sensitive mass around the Z direction. For an idealized (non mechanically coupled) silicon micro mechanical gyroscope, only the driving mode is excited, and if there is no external angular velocity input, the gyroscope output is zero. The sensitive acceleration generated by the measured Coriolis force and mechanical coupling is shown in Figure 2. The displacement of the center of mass is proportional to the coupling of stiffness and driving displacement, and is orthogonal to the phase of the driving velocity signal. Therefore, the stiffness coupling error will cause orthogonal coupling motion of the gyroscope. The interference force formed by damping coupling error is proportional to the driving speed, and this force is in phase with the driving speed signal and the Coriolis acceleration signal. Due to the high Q value of silicon micro gyroscopes, especially in vacuum silicon micro gyroscopes, damping interference can be ignored. diode