为了提高空间光通信PAT系统的扰动抑制能力，提出了一种基于扰动观测器的控制方法。该方法首先对PAT系统进行分析，得到简化的控制模型，然后利用扰动观测器从电机转动位置和光斑位置中观测出扰动，最后将扰动等效补偿量加入到电流环前的综合点。精跟踪系统的仿真实验结果表明：相比常规的PD控制器，加入扰动观测器使扰动隔离度在电机电流饱和前的几乎所有频率处都得到了提升，最优情况可达到28.2 dB；同时，该方法具有很强的鲁棒性，在系统物理参数变化15%时扰动隔离度依然比没有使用扰动观测器时提高了至少1倍。所述的控制方法显著提高了PAT系统的抗扰动性能，对大范围与高动态的精密光电跟踪系统有一定的参考价值。

In order to improve the disturbance isolation degree for space optical communication Pointing, Acquisition, and Tracking(PAT) system, a novel control method based on disturbance observer was proposed. Firstly, according to the structure analysis of PAT system, the simplified system model was gained and then the disturbance was observed from the position of the motor and the laser spot by disturbance observer. Finally, the equivalent amount of disturbance compensation was added to the integration points in front of the current loop. The simulation results of fine tracking system show that compared with the traditional PD controller, adding the disturbance observer can improve the disturbance isolation degree at almost all frequencies before the motor current saturates, and the optimal situation has reached 28.2 dB. Meanwhile, this method has strong robustness; the disturbance isolation degree still increases by at least 1 times than not using the disturbance observer when there are 15% changes for the system physical parameters. The proposed control method greatly improves the disturbance isolation degree for PAT system and is of certain reference value to the wide range and high dynamic precision photoelectric tracking system.