考虑系统扰动对光电跟踪伺服系统精度的影响，提出了采用自抗扰的控制方案，并分析了实现自抗扰的工作原理。对某型光电跟踪系统进行了结构分析，将目标运动速度视为外部扰动，系统内部参数摄动视为内部扰动，采用扩张状态观测器从系统响应的输入、输出信号中估计出扰动，并进一步用跟踪微分器提取扰动的一阶导数来提高对扰动的估计精度，以最大程度地补偿扰动。实验结果表明,在载体扰动下，跟踪最大角速度为40 mrad/s，最大角加速度为8 mrad/s2，机动目标的误差＜0.1 mrad，且响应速度快,超调＜10%。该方案结构简单，控制鲁棒性强；无需额外的传感器对目标运动进行测量、滤波和预测，即可有效提高系统高精度捕获、跟踪快速机动目标的能力。

An active disturbance rejection controller for an electro-optical tracking servo system is presented to track maneuvering targets fast and accurately and then its work principle is investigated. Based on the structure analysis of a tracking system, the target velocity is taken as the exterior unknown disturbance and the system parameter change is used as the interior unknown disturbance. A extend state observer and a tracking differentiator are used to estimate the disturbance accurately from the input and output information of system response, then the controller can compensate the disturbance further. Experimental results indicate that the system can fast track maneuvering targets at a maximal angular velocity of 40 mrad/s and an maximal angular acceleration of 8 mrad/s2 while the maximal tracking error and the maximal overshoot are less than 0.1 mrad and 10% respectively.These results show that the scheme has a good structure and robust performance, and can satisfy the system requirements without using the sensor to measure the target state.