Novel mismatch compensation methods for rate-integrating gyroscopes

We propose two new controls to improve the performance of rate-integrating MEMS gyroscopes (RIGs). The first control loop dynamically determines and compensates for damping mismatch by creating a force on the gyroscope to oppose the apparent force due to damping mismatch. The second control loop extends this concept to frequency mismatch to eliminate residual quadrature which would otherwise accumulate due to lag in the control system. The proposed control loops have been investigated using simulation results from a non-ideal gyroscope including frequency and damping mismatch as well as control delay and capacitive feed-through. Experimental results of the controls being applied to a MEMS rate-integrating gyroscope are also presented. In simulation, the controls can reduce the drift in a gyroscope by better than two orders of magnitude. In a physical gyroscope, the mismatch parameters do not match the normal first order model, however RMS drift is reduced by 25%.