セグメント高速ステアリングミラー用圧電駆動型アクチュエータの開発

抄録

Laser scanning systems for laser micro drilling and optical inter-satellite communication have required fast steering mirrors (FSMs) with a large diameter. However, increasing the mirror diameter makes the fast positioning more difficult because the elastic mode of the mirror occurs at a lower frequency. To solve the problem, a segmented FSM, in which several small mirror actuators having higher natural frequencies work together to produce the same reflective surface as a large mirror generates, is proposed. The final target of this research is to achieve a bandwidth of 10 kHz and more with a reflective surface of 50 mm in diameter. For the verification of the feasibility, a multi-axis, high response and small mirror actuator having a single hexagonal mirror with a distance between opposite sides of 18 mm was designed and tested. Each small mirror made of SiC is driven by a combination of tip-tilt and piston drivers using piezoelectric actuators. The fabricated small mirror actuator realized the first natural frequency over 10 kHz. The prototype is tested by a feedback controller with integrators and notch filters. The designed controller achieved the target bandwidths of 10 kHz in all the driving directions.