分类： 天文学 >> 天文仪器与技术 提交时间： 2024-06-06 合作期刊: 《天文技术与仪器（英文）》
摘要：The primary mirrors of current and future large telescopes always employ a segmented mirror configuration. The small but non-negligible gaps between neighboring segments cause additional diffraction, which restricts the performance of high-contrast coronagraph. To solve this problem, we propose a coronagraph system based on a single liquid crystal spatial light modulator (SLM). This spatial light modulator is used for amplitude apodization, and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent (SPGD) algorithm to control the spatial light modulator, which is based on point spread function (PSF) sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function. The system delivers a contrast in the order of 10−6, and shows excellent potential to be used in current and future large aperture telescopes, both on the ground and in space.
分类： 天文学 >> 天文仪器与技术 提交时间： 2024-06-06 合作期刊: 《天文技术与仪器（英文）》
摘要：Research on adaptive deformable mirror technology for voice coil actuators (VCAs) is an important trend in the development of large ground-based telescopes. A voice coil adaptive deformable mirror contains a large number of actuators, and there are problems with structural coupling and large temperature increases in their internal coils. Additionally, parameters of the traditional proportional integral derivative (PID) control cannot be adjusted in real-time to adapt to system changes. These problems can be addressed by introducing fuzzy control methods. A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process, and a prototype platform has been established to verify the effectiveness and robustness of this process. Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative (Fuzzy-PID) controllers, showing that, in system step response tests, the fuzzy control system reduces rise time by 20.25%, decreases overshoot by 78.24%, and shortens settling time by 67.59%. In disturbance rejection experiments, fuzzy control achieves a 46.09% reduction in the maximum deviation, indicating stronger robustness. The Fuzzy-PID controller, based on table lookup, outperforms the standard controller significantly, showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.
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