With the rapid development of modern optical detection technology, higher requirements are put forward for optical detection equipment. Whether it is a ground optical measuring instrument or a space detection camera, it is necessary to reduce or avoid the measurement performance degradation caused by the interference of strong light sources such as the sun.It briefly introduces the current application development of the sunshade deployment mechanism, comparatively analyzes some problems of the current application schemes, and proposes a design scheme of the ropes driven sunshade deployment mechanism. The traction of the constant pressure exhaust valve during the first deployment stage can be achieved by rope traction, which can quickly realize the air pressure balance between the target instrument to be sealed and the external environment, and can avoid the air pressure shock caused by the sealing failure in the initial deployment stage of the sunshade deployment mechanism; Rope traction can effectively control the speed of the unlocking process in the second stage of deployment, reducing the shock of the unlocking moment again; In the third stage of deployment, locking of the deployment joint can be achieved by rope traction, and locking backup can be effectively achieved. This kind of ropes driven sunshade deployment mechanism has the advantages of not only controllable deployment process, small shock, but can be used repeatedly without damaging or destroying the original deployment locking mechanism, and is especially suitable for ground measuring equipment and the ground repeated principle verification of space detection instruments.
In order to meet the requirements of high-precision alignment of primary and secondary mirrors of space camera in
thermal environment, we develop a new supporting structure which can eliminate heat affect between mirrors
automatically. Through the simulation analysis, we have verified this structural design is feasible. According to
requirements of the optical system, an integrated machining scheme with three-bar supporting structure for the secondary
mirror is proposed. The automatic athermalization of the primary and secondary mirrors supporting structure is
confirmed by structural analysis and optimization. The displacement between the primary mirror and secondary mirrors
in the thermal environment range of -20° ~ +60°C is analyzed by using the PATRAN software, and the results show the
position change is within 0.01mm. The structural size of the secondary mirror supporting cylinder is optimized, and the
effect of stray light suppression for the multilayer sleeve visor is analyzed and verified by using the TRACEPRO
software. The results show that the proposed structural design can achieve the high stability of the primary and
secondary mirrors supporting structure and the good effect of stray light suppression.
The Nanshan radio telescope (NSRT) is a fully steerable radio telescope with a diameter of 26 meters, located in Urumqi, Xinjiang, China. The NSRT currently operate in the frequency range from 1.4 GHz to 22.4 GHz。In order to reduce effect of gravity-induced structural deformations on antenna efficiency and pointing accuracy, the subreflector adjustment system has been used to adjust subreflector position in 6 degree-of-freedom to correct subreflector defocusing and reflectors misalignment. The Stewart platform is used as the adjustment mechanism to perform translation -50/+50 mm (along x, y, z axis) and rotation -5/+5 degree (with respect to x, y axis) with repeated positioning accuracies of 0.07 mm (translation) and 0.01 degree (rotation). The paper will mainly introduce an overview of the NSRT subreflector adjustment system, including Stewart platform and control system, performance testing, and position adjustment of subreflector.
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