A Closed-Loop Mode-Localized Accelerometer

This paper reports a closed-loop mode-localized accelerometer for the first time. The accelerometer utilizes weakly coupled single-tine resonators as the sensing element to decrease the number of vibration modes. Based on a proposed closed-loop readout technique, the transient responses of the mode-localized accelerometer can be measured directly in the time domain. The test results show that the measured amplitude ratio noise and the resolution under closed-loop circumstances are 1.409×10^-5 Hz and 7.608μg Hz, respectively, which are largely improved compared with those (9.883×10^-4 Hz and 0.744 mgHz) under the open-loop measurement. The sensitivity based on the amplitude ratio readout is 124 times higher than that of the frequency with the acceleration input of [-1g, +1g], which indicates that the high sensitivity of the mode-localized sensors can be also obtained utilizing closed-loop control.