  This paper demonstrates a vibration test for a resonant MEMS scanning system
in operation to evaluate the vibration immunity for automotive lidar
applications. The MEMS mirror has a reinforcement structure on the backside of
the mirror, causing vibration coupling by a mismatch between the center of mass
and the rotation axis. An analysis of energy variation is proposed, showing
direction dependency of vibration coupling. Vibration influences are evaluated
by transient vibration response and vibration frequency sweep using a single
tone vibration for translational y- and z- axis. The measurement results
demonstrate standard deviation (STD) amplitude and frequency errors are up to
1.64 % and 0.26 %, respectively, for 2 grms single tone vibrations on y axis.
The simulation results also show a good agreement with both measurements,
proving the proposed vibration coupling mechanism of the MEMS mirror. The
phased locked loop (PLL) improves the STD amplitude and frequency errors to
0.91 % and 0.15 % for y axis vibration, corresponding to 44.4 % and 43.0 %
reduction, respectively, showing the benefit of a controlled MEMS mirror for
reliable automotive MEMS lidars.
