Adaptive force-balancing control of MEMS gyroscope with actuator limits

This work presents an adaptive force-balancing control (AFBC) scheme with actuator limits for a MEMS Z-axis gyroscope. The purpose of the adaptive force-balancing control is to identify major fabrication imperfections so that they are properly compensated unlike the case of conventional force-balancing controlled gyroscope. The proposed AFBC scheme controls the vibratory modes of the proof mass while ensuring that the control input satisfies the magnitude constraints and the performance of the gyroscope is enhanced in the presence of fabrication uncertainties. Consequently, commonly reported problems of MEMS gyroscope such as quadrature compensation, drive and sense axes frequency tuning are not needed and closed-loop identification of the angular rate is now possible without measuring the input/output phase difference. The proposed scheme also compensates the cross-damping terms that cause the zero-rate output (ZRO). Simulation results justify theoretical conclusions.