大行程磁液变形镜的线性响应特性分析

摘要

The stroke of the wave-front corrector is a key factor that determines its correction ability in the adaptive optics systems. The stroke of the current wave-front correctors, i.e. solid deformable mirrors, is small and far from enough to meet the requirement of large aberration corrections. A large stroke Magnetic Fluid Deformable Mirror (MFDM) was presented, where the linearization of the response of the MFDM was obtained by superimposing a large uniform magnetic field generated by Maxwell coil to the small magnetic field generated by the micro-electromagnetic coils. The proposed fluid mirror can easily supply a large stroke of the surface deflection more than 100 µm. The linearized surface analytical model of the MFDM was first built. Then the magnetic fields produced by Maxwell coil and micro-electromagnetic coils and the linearization response characteristic of the MFDM were simulated in COMSOL multiphysics EFA environment combined by MATLAB software. Finally, the simulation results were verified experimentally based on a designed prototype MFDM. The results show that the developed analytical model can correctly represent the characteristics of the MFDM, and the large stroke more than 100 µm can be obtained with small current inputs to the micro-electromagnetic coils under the large uniform magnetic field generated by the Maxwell coil.%波前校正器的行程是影响其校正能力的关键因素，现有固态变形镜的变形行程较小，还不能完全满足自适应光学系统对光波畸变的校正能力要求。针对该问题，本文提出并设计一种大行程磁液变形镜系统，通过Maxwell 线圈和微小电磁驱动线圈产生的磁场来控制磁液变形镜的镜面变形，可提供高达100μm 以上的变形行程。本文首先建立了磁液变形镜线性解析模型，然后采用多物理场有限元仿真软件COMSOL对通电Maxwell线圈和微线圈产生的磁场进行仿真分析，并结合 MATLAB 数值仿真软件，对大行程磁液变形镜的响应特性进行仿真分析，最后基于制作的磁液变形镜原型样机对仿真结果进行实验验证，结果验证了镜面线性解析模型的正确性，在Maxwell线圈产生的均匀磁场中，向微电磁线圈输入微小电流即可产生100μm以上的大行程镜面变形。