为解决光电跟踪伺服系统受电机力矩波动影响产生的速度波动问题，提出了一种改进的自抗扰控制策略进行力矩波动补偿。该算法主要由两部分组成：通过扩张状态观测器辨识出系统扰动，然后将该扰动前馈到系统控制量中去，构成复合校正系统；反馈通道中采用两参数的比例微分控制器，可以保证系统的稳定性和良好的动态特性。仿真分析和实验结果表明：与同等闭环控制带宽的 PI控制器相比，自抗扰控制器可以提高系统对扰动力矩的抑制能力，采用自抗扰补偿时，速度误差的峰值由 1.88%降低到 0.65%，速度误差的均方根值由 0.8%降低到 0.2%。实验结果证明提出的方法能够有效降低电机力矩波动的影响，提高速度平稳性。

An improved active disturbance rejection control is proposed to solve the problem on the velocity fluctuation caused by torque ripples in a DC torque motor. The algorithm consists of two parts: the extended state observer estimates the system disturbances, and then the estimated disturbance is fed into the control system to form composite correction system. A two-parameter proportional-derivative controller can guarantee system stability and good dynamic characteristics. The simulation and experimental results show that, compared to the PI controller with the same closed-loop control bandwidth, the proposed method can improve the ability of disturbance rejection, using Active Disturbance Rejection Control (ADRC) compensation, the peak-peak value of speed error from 1.88% down to 0.65%, the Root Mean Square (RMS) value of the error from 0.8% to 0.2%. Experimental results show that the proposed method can effectively reduce the velocity fluctuation caused by motor torque ripple, and improve the speed smooth.