Design and assessment of a micro-nano positioning hexapod platform with flexure hinges for large aperture telescopes
Xuewen Wang, Yang Yu, Zhenbang Xu, Chunyang Han, Jialin Sun, Jianli Wang
Abstract
In order to compensate the optical system bias, which is caused by the change of elevation angle and thermal gradient during the optical alignment of the telescope, a novel high stiffness micro-nano positioning hexapod platform with flexure hinges is proposed in this paper. The novel flexure hinge has a mechanical limit, and its equivalent model is established and analyzed. In addition, in order to speed up the solution process, a novel simplified inverse kinematic model is developed based on the rigid body kinematic theory. Then, an effective rigid-flexible coupling simulation system is built to verify the correctness and applicability of the inverse kinematic model. Finally, a systematic experimental test method and a statistical-based data analysis theory are proposed. The experimental results show that the resolution and repeatability of translation and rotation and lateral stiffness are as follows: 0.3 mm and 0.5 arc sec, ± 0.5 µm and ±0.5 arc sec, 131.6N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>⋅</mml:mo> </mml:math> µm -1 and 133.0N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>⋅</mml:mo> </mml:math> µm -1 . The proposed hexapod platform can be used to correct the optical system bias of large-aperture telescopes.