Beam-steering MOEMS system based on a resonant piezoMEMS mirror and a phase-locked loop controller

This work aimed to create a beam steering system based on a resonant micromirror with a control drive and sense modules implemented with low-voltage electronics and piezoelectric actuation and sensing. Solution's optimization goal was to create scalable architecture with minimal power consumption and reduce an overall MOEMS system size. We applied a direct digital control methodology for resonant piezoelectric elements by designing a level-translating electronics to directly interface actuator and sense elements with MAX1000 FPGA development board. This implementation merged control and measurement loops into VLSI design operating in the FPGA. The system behavior studied with 2D-scanning mirrors featuring an in-house piezoelectric MEMS-platform with AIN patterned actuation and sensing elements by measuring the generated laser reflection and pattern cross-correlating it with electrical signals. The developed MOEMS system provides the means for 2D optical scanning with a 1.8V logic level drive. Characterization results presented, study a mirror reflection pattern correlation with optical signals, and implemented control methods enabled frequency control with feedback in all operating conditions. The mirror feedback loop in the time domain provides reliable phase delay and oscillation period information. The calibrated look-up table post-processing module leverages this information and calculates the mirror's angular position at a given moment in time. The direct digital interface with a resonant piezoelectric mirror can deliver controllable beam steering in a single-supply, low-voltage, and high integration environment. The digital control loop allows for measurement and adjustment on a cycle-to-cycle basis, enabling further algorithm development for advanced functions like cross-sensor compensation, safety, and sensor fusion.