Integrated model reference adaptive control and time-varying angular rate estimation for micro-machined gyroscopes

Abstract

Owing to the imposed but undesired accelerations such as quadrature error and cross-axis perturbation, the micro-machined gyroscope would not be unconditionally retained at resonant mode. Once the preset resonance is not sustained, the performance of the micro-gyroscope is accordingly degraded. In this article, a direct model reference adaptive control loop which is integrated with a modified disturbance estimating observer (MDEO) is proposed to guarantee the resonant oscillations at drive mode and counterbalance the undesired disturbance mainly caused by quadrature error and cross-axis perturbation. The parameters of controller are on-line innovated by the dynamic error between the MDEO output and expected response. In addition, Lyapunov stability theory is employed to examine the stability of the closed-loop control system. Finally, the efficacy of numerical evaluation on the exerted time-varying angular rate, which is to be detected and measured by the gyroscope, is verified by intensive simulations.

Keywords:

• model reference adaptive control
• disturbance estimation observer
• micro-gyroscope
• MEMS

Acknowledgements

The authors would like to thank the Center for Micro/Nano Technology Research, National Cheng Kung University, Tainan, Taiwan, and National Nano Devices Laboratory (NDL) for equipment access and technical support. This research was partially supported by National Science Council (Taiwan) with Grant NSC99-2622-E-006-010-CC2.