Adjusting the Vibratory Response of a Micro Mirror via Position and Velocity Feedback

Abstract

We changed the vibratory (dynamic) response of a micro mirror experimentally using a feedback circuit. For this purpose, we first measured the vibrational velocity of the mirror using a Laser Doppler Vibrometer and then multiplied it with a gain and fed the signal back to the mirror to change its effective damping. We also investigate the influence of velocity and position feedback on the dynamic response of the same mirror through numerical simulations. For this purpose, first, a transfer function of the mirror was obtained based on the experimental frequency sweep data of the first two vibration modes. Then, the dynamic response of the mirror was investigated for different feedback gains via simulations. The results of our study show that the vibration amplitude or settling time of the mirror can be adjusted by altering the velocity feedback gain and the coupled vibration modes of the mirror can be separated from each other by adjusting the position feedback gain.

New observation on automatic phase adjustment of a smart cantilever resonator

“…When the system is switched ON the piezoelectric sensor responds to the noise and produces a small voltage, which is amplified by the maintaining amplifier to build up a steady-state oscillating condition. The required gain is obtained by designing the value of the feedback resistance of the maintaining amplifier and the required phased is obtained by designing the value of the resistor and the capacitor of RC network, which makes the mass measurement system oscillate at its resonant frequency (Suresh et al, 2011b;Veryeri and Basdogan, 2011). The closed-loop resonant circuit tracks the change in resonance frequency and vibrates the beam with the new resonance frequency whenever the mass on the cantilever beam changes.…”