NEW DESIGNS OF MICROMACHINED VIBRATING RATE GYROSCOPES WITH DECOUPLEDOSCILLATION MODES

This paper reports on new vibrating comb-drive rate gyroscope designs featuring decoupling of the actuation and the detection mode. Analytic al calculations as well as FEM and system simulations are carried out. It is investigated how to overcome the main drawbacks of these sensor s, which are especially the frequency mismatch of the two oscillation modes, the insufficient bandwidth and the effects of levitation. Conce pts and simulations of electrostatically controlling both the resonanc e frequency and the bandwidth are presented. Within these concepts no mechanical balancing of the device is required and thus calibration co sts are reduced. Simulations of a new quasi-rotating rate gyroscope sh ow that a resolution of 0.1 degrees s(-1) is possible at a bandwidth o f 50 Hz with 6 mm(2) sensor area only, and that the effects of levitat ion are actually compensated. The design has been fabricated within th e Bosch Foundry process. First measurements of the angular rate show a resolution of 0.5 degrees s(-1) in a 50 Hz bandwidth. (C) 1998 Elsevi er Science S.A. All rights reserved.