Experimental Evaluation of Vibration Influence on a Resonant MEMS Scanning System for Automotive Lidars

Y This article 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 the 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.

Automated summary

This article presents a vibration test method for evaluating the vibration immunity of a resonant MEMS scanning system used in automotive lidar applications. The energy variation analysis reveals the direction dependency of vibration coupling. Both experimental and simulation results verify the proposed vibration coupling mechanism of the MEMS mirror, and a controlled MEMS mirror using a phase locked loop (PLL) is shown to improve system performance.