Coriolis force angular rate sensor

Figure 18.10 Schematic of a Coriolis force angular rate sensor. The ring/disk structure is stimulated to vibrate in plane (a). Applying an angular movement leads to a deflection of the disk, which is measured capacitively (b).

Figure 18.13 Coriolis force angular rate sensor chip (a) (Zwicker (2008), Copyright 2007, John Wiley and Sons, used with kirulpermission.), and the sensor in a package (b). The size of the sensor structure is about 2.0 x 1.2 mm.

For the following example, the function is not directly obvious from Fig. 7.2.1. A flat disc-shaped rotor, suspended by flexible beams at a central point, is set into horizontal, rotational vibrations by comb drive structures. If a turning movement occurs in the plane of the sensor chip, the rotor responds with a perpendicular tilt due to the conservation of angular momentum by Coriolis forces. The distance of the rotor disc to the substrate is detected capacitively and provides a signal proportional to the yaw rate. As the rotary oscillation periodically changes its direction, the whole structure executes tilt oscillations towards the substrate with the frequency of the drive (Fig. 7.2.14, Fig. 7.2.15). 

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