基于闭环反馈控制理论，对神光－Ⅲ3光源自动准直系统进行设计，分析系统的工作原理、控制算法和软件控制流程。对准直过程中电动控制对于控制结果影响的变化规律建立了数学模型，旨在克服俯仰和方位相互联动对准直精度的影响。采用二维镜架自动准直方案，使准直偏差在预定调整范围内不断收敛。神光－Ⅲ调试现场的准直结果证明：该自动准直系统达到了设计要求，即自动准直系统在半小时内完成8路光束的光束准直，其角度误差≤5．0%／空间滤波器小孔直径，平移误差≤1．0%(光束近场直径精度)。

The SG-Ⅲ 3ω laser auto-collimation system and its control algorithm are studied based on loop feedback control theory. The operation principle,control algorithm and software control flowchart of the system are analyzed. The mathematical model for the impact of motorcontrol on the control result during the collimation process was established to overcome the side effects on the collimating accuracy caused by the crosstalk of both azimuth and elevation motors. By adopting the auto-collimation scheme with two-dimensional mirror mount,the collimating error converges continuously in the given precision range. The results of the test on the spot show that this SG-Ⅲ auto-collimation system meets the design specification. The SG-Ⅲ 3ω laser auto-collimation system can fulfill the collimation of 8 beams in half an hour. The angle error of the system is less than 5% for pinhole diameter per space domain,and the translation error is less than 1.0% for the accuracy of the near-field beam diameter.