Research On The Actuator For Astronomical Telescope Panel

At present,large astronomical telescopes usually use active reflector technology.In this technique,the reflecting surface of telescope is composed of many panels.Each panel usually need more than 3 micro-displacement actuators to support and adjust quickly,so as to realize the pitching,deflection and translation of sub-panel and achieve high precision requirement of the reflecting surface.The micro-displacement actuator as a supporting and regulating mechanism with precision linear displacement output,requires high resolution(micro-nano level),high stability,high rigidity,high repeatability,large load performance and millimeter-level stroke.Therefore,it is of great scientific significance and practical value to research the micro-displacement actuators used on the panel of astronomical telescope in the Antarctic.Based on the advantages of the traveling wave rotary ultrasonic motors,a micro-displacement actuator for the astronomical telescope panel and a corresponding driving controller prototype are designed and developed.The performance evaluation experiments and environmental simulation experiments are carried out to verify the feasibility of its application in the Antarctic.The main contents of this paper are as follows:1.Designed and made a prototype of micro-displacement actuator with reference to the requirements of the pre-research project "DATE5"(5m Dome A Terahertz Explorer).Considering the Antarctic high humidity and low temperature environment,the actuator's overall seal design is carried out to avoid the mechanism freezing at low temperature.2.The micro-displacement actuator take the traveling wave rotary ultrasonic motor as the driving source,the transmission part uses the differential thread shaft to convert the motor's rotation motion into the linear motion of the output end,and completes the precision improvement of the micro-displacement actuator and the adjustment of the displacement.3.In view of the influence of the low temperature environment on the transmission structure of the actuator,the ultrasonic motor and its driving and control system,the driving power is optimized through the experiment.The driving control system is matched and coordinated according to the change of the performance of the ultrasonic motor at low temperature.4.An experimental test system at normal temperature and low temperature is established.The performance of the micro-displacement actuator is evaluated,including effective travel detection,the stepping precision detection,repeatability precision detection,location precision detection,linearitydetection and return clearance detection.The stepping precision of the micro-displacement actuator at room temperature and at minus 40 degrees is 1?m±0.07?m and 1?m±0.16?m respectively,which all achieve the design goal.The research shows that the traveling wave rotary ultrasonic motor by differential thread convert rotary motion to linear motion principle,has high resolution,high stability,high rigidity,high repeat precision,large load performance and millimeter travel etc,which can be used to support and adjust the micro-displacement of the Antarctic radio telescope mirror panel.