Analysis and design of a 3rd order velocity-controlled closed-loop for MEMS vibratory gyroscopes

Sensors (Basel). 2013 Sep 18;13(9):12564-80. doi: 10.3390/s130912564.

Abstract

The time-average method currently available is limited to analyzing the specific performance of the automatic gain control-proportional and integral (AGC-PI) based velocity-controlled closed-loop in a micro-electro-mechanical systems (MEMS) vibratory gyroscope, since it is hard to solve nonlinear functions in the time domain when the control loop reaches to 3rd order. In this paper, we propose a linearization design approach to overcome this limitation by establishing a 3rd order linear model of the control loop and transferring the analysis to the frequency domain. Order reduction is applied on the built linear model's transfer function by constructing a zero-pole doublet, and therefore mathematical expression of each control loop's performance specification is obtained. Then an optimization methodology is summarized, which reveals that a robust, stable and swift control loop can be achieved by carefully selecting the system parameters following a priority order. Closed-loop drive circuits are designed and implemented using 0.35 μm complementary metal oxide semiconductor (CMOS) process, and experiments carried out on a gyroscope prototype verify the optimization methodology that an optimized stability of the control loop can be achieved by constructing the zero-pole doublet, and disturbance rejection capability (D.R.C) of the control loop can be improved by increasing the integral term.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acceleration*
  • Accelerometry / instrumentation*
  • Computer Simulation
  • Computer-Aided Design
  • Equipment Design
  • Equipment Failure Analysis
  • Feedback
  • Micro-Electrical-Mechanical Systems / instrumentation*
  • Models, Theoretical
  • Transducers*
  • Vibration