光学天文望远镜用微位移驱动器机构研究综述

Review of Mechanical Structure of Micro-displacement Actuator for Optical Astronomical Telescope

该文回顾光学天文望远镜拼接镜面主动光学技术中的微位移驱动器的应用,介绍了微位移驱动器的工作原理、机械结构以及性能要求。概述了微位移驱动器的基本组成机构,并结合目前应用于天文望远镜的具体实例,比较了其优缺点。最后针对未来极大口径天文望远镜中的应用要求,对微位移驱动器的发展趋势提出展望。

The dilemma of the large diameter of mirror needed in modern astronomy against the limitation of manufacturing process is resolved by the segmented mirror active optics technology , which has been widely used in large aperture infrared/optical astronomical telescopes. To meet the performance requirements of co-focusing and co-phasing in segmented mirror active optics, micro-displacement actuators with nanometer resolution and millimeter stroke are necessary. Micro-displacement actuators are reviewed from the structural point of view for optical astronomical telescopes involving segmented mirror active optics. The emphasis is on working principle, performance requirement and mechanical structure of the actuators. Various basic functional components of actuator are described to figure out pros and cons based on current applications in astronomical telescopes. Seeing that, flexure exhibits excellent mechanical properties free of friction, clearance, and lubrication, it is extensively used in displacement pantograph mechanism and guide mechanism to attain fine resolution of movement transmitting. In addition, novel intelligent materials are introduced to development of actuators. Giant magnetostrictive material with the solid-state deformation principle has the potential to render high force and precise displacement with small volume, making it suitable to realize efficient miniature actuators for astronomical telescopes. Piezoelectric ceramics can generate precise deformation even at high-frequency band, which enables them capable for adaptive optics. To meet technical requirements for future extremely large telescope, the development tendency of micro-displacement actuator is further discussed.