针对大口径光电望远镜惯量大、存在摩擦非线性的特点，设计了自抗扰控制器以改善伺服系统的速度响应特性。介绍了自抗扰控制器的工作原理和基本结构，给出了控制器参数的选择依据，并仿真分析了各个参数的作用效果。最后，在实际望远镜转台上和常规PID控制器进行了对比实验。结果表明，采用自抗扰控制器，既可以实现大速度阶跃响应快速无超调，又可以缩短低速阶跃响应时间、改善低速平稳性。在以0.005 (°)/s速度运行时，系统稳定时间为1 s，速度波动标准差为0.000 082 (°)/s，最大值为0.000 42 (°)/s，性能明显优于传统的PID控制系统。实验结果证明自抗扰控制器对摩擦、饱和等非线性因素具有抑制能力，可以提高望远镜伺服系统的调速性能。

According to the characteristics of a large optical telescope by large inertia and nonlinear frictions, an Active Disturbance Rejection Controller (ADRC) was designed to improve the response speed of the servo system. The working principle and basic structure of the ADRC was introduced,the regulation of parameters for the ADRC was given, and each parameter was analyzed imitatively. Finally, the ADRC was compared with conventional PID controllers. Actual results show that the ADRC can not only achieve a higher response speed without a overshoot, and its low-speed step response time can be shortened and the low-speed smoothness be improved.When it runs in 0.005 (°)/s, the system settling time is 1 s, the standard deviation of velocity fluctuation is 0.000 082 (°)/s (maximum in 0.000 42 (°)/s).The results demonstrate that the performance of the ADRC is better than that of the traditional PID controller. Experimental results show that the ADRC can inhibit friction, saturation and other nonlinear factors, and can improve the speed performance of the telescope servo system.