No abstract

Not only could the segmented mirrors synthetic aperture optical system improve the sensitivity and resolution of telescope system, but also meet the demands of NGST (next generation space telescope).In order to ensure segmented mirrors keep the same optical performance of mono-mirror, that is, the phase error less thanλ/20，each segmented mirror should have its own nano-grade high precision correcting device. In this paper, the synthetic aperture is composed of three segmented mirrors, one fixed and the other two adjustable, each of which achieved 6-DOF adjustment by three micro-displacement actuators and the characters of the actuators are researched. For the purpose of nano-grade positioning, PZT is used as the micro-displacement actuator. In our research, the jointing process is rough-tuned by mechanical structure before fine-tuned by PZT, so there's no need for the PZT to work in the full range. In order to provide basic support for nano-grade phase error correction, it is very necessary to calibrate the relationship between the elongation distribution of each PZT and the regulating voltage for each actuator, in its own scope of work with small step, because of the hysteresis of PZT.