Open-loop control demonstration of micro-electro-mechanical-system MEMS deformable mirror.

Area of Science:

• Astronomy and Astrophysics
• Optical Engineering
• Instrumentation Science

Background:

• Advanced astronomical observations require sophisticated adaptive optics (AO) systems.
• Micro-Electro-Mechanical-System (MEMS) deformable mirrors (DMs) are crucial for Multi-Object AO (MOAO) and Extreme AO (ExAO) but face control challenges.
• Current research focuses on modeling MEMS DMs for open-loop control, a key barrier for MOAO implementation.

Purpose of the Study:

• To develop and validate a computationally efficient open-loop control strategy for MEMS DMs.
• To characterize MEMS DMs for improved performance in AO systems.
• To reduce reliance on complex modeling techniques like plate equations.

Main Methods:

• Performed a thorough characterization of a MEMS DM.
• Calibrated the actuator stroke-voltage relationship and actuator influence functions.
• Employed a simpler control approach based on the additivity of influence functions, avoiding heavy modeling.

Main Results:

• Achieved a mean residual open-loop root-mean-square (rms) error of 16.5 nm.
• Obtained a mean fitting error rms of 13.3 nm.
• The mean DM error rms was 10.8 nm, representing 11% of the residual error, demonstrating the model's performance.

Conclusions:

• The developed open-loop control strategy using influence function additivity is effective for MEMS DMs.
• This approach offers a simpler alternative to complex modeling for AO systems.
• The results show promise for the on-sky demonstration of MEMS DMs in future AO systems.