关键词: 分块式空间望远镜, Zernike多项式, 合像, 微振动, 音圈电机, 整星动力学

Abstract: Facing the problem of high precision image combination and image stabilization adjustment of the primary mirror of the segmented space telescope assembled on orbit, a 6 DOF sub mirror active adjustment mechanism driven by voice coil motor is designed in this paper. Considering the influence of the micro vibration source of the star, a decentralized force control scheme is proposed, which completes high precision control of the mirror's position and attitude. And the image combination and vibration control of the segmented mirror is realized. In this paper, the form of optical sensitivity matrix between aberration and sub mirror pose parameters is derived, and Zernike aberration polynomial of hexagonal aperture is obtained by Gram Schmidt orthogonalization method. Secondly, the whole satellite dynamics model of the segmented space telescope is established. Based on the voice coil motor, a 6 DOF sub mirror active adjustment mechanism is designed, and the position and attitude solutions scheme of the eddy current sensor array are proposed. Then, the control scheme of the segmented space telescope after on orbit assembly is proposed. Aiming at the TTP (tip, tilt, piston) error and micro vibration interference of the sub mirror, the decentralized voice coil motor controller with feed forward compensation and speed feedback is designed via the analytic expression of the position and attitude target quantity of the sub mirror and the expected length of the actuator to adjust the motor output force and the position and attitude of the sub mirror, so as to achieve image combining and vibration control. Finally, the simulation verification and calculation of the imaging quality evaluation index show that the control scheme proposed in this paper can achieve high precision image merging and image stabilization adjustment of the segmented space telescope, with fast adjustment speed, high accuracy and strong vibration attenuation.

Key words: segmented space telescope, zernike polynomial, image merging, micro vibration, voice coil motor, whole satellite dynamics