Simulation of a MEMS Coriolis gyroscope with closed-loop control for arbitrary inertial force, angular rate, and quadrature inputs

Abstract

A closed-loop control system for a MEMS gyroscope is proposed which greatly restricts the mechanical freedom of the sense mass while accurately measuring the total external force acting upon the sense mass. This is realized by an algorithm which uses the previous three sense mass position measurements to generate a position-, velocity-, and acceleration-dependant feedback force on the sense mass. The feedback force is equal and opposite to the average total external force the sense mass was subject to during the previous three position samples. As the feedback sampling rate increases, so too does the control loop's ability to both spatially confine the sense mass and determine the total external force acting on the sense mass. For a 1.05 MHz feedback sampling rate, we achieve a measurement of the external force with less than 5 parts per million error, and constrain the sense mass to displacements of less than 10nm.