With the aim to attenuate the effect of wind load disturbance on the tracking precision and the life-span of a large deep space observatory antenna,this paper proposed a wind disturbance rejection servo system.As disturbance observer can improve the system performance,the mechanism of electrical motor was utilized to simplify the design process.The feedback channels of current and speed control as well as load impact were regarded as parts of the total disturbance,and the lags in the feedforward channels were approximated by their steady gains respectively.Therefore,the required order of the extended state observer,which was employed to estimate the total disturbance,including the wind load torque and other uncertain mechanical dynamics,could be substantially reduced.Then,the total disturbance was compensated by the observer.Furthermore,the limit cycle was eliminated in the presence of friction according to the describing function method.Finally,mathematical simulations and experiments were carried out.In the experiment,the overshoot is reduced by 34％ and the capacity of gust rejection is increased by 60％,respectively,as compared with that of traditional equipment,while the tracking precision is also raised significantly.The objective of rejecting the wind gust disturbance for the large deep space observatory antenna system can be achieved by using the proposed method.%为了改善风载荷干扰对深空探测天线跟踪精度和寿命的影响,设计了位置环线性自抗扰控制器.由于扰动观测器可以改善系统性能,本文基于电机动力学机理,将电流与速度的反馈与负载的影响作为总扰动的一部分,通过静态增益对前向通道的惯性环节进行近似,极大地降低了扩张状态观测器的阶次;采用在线估计和补偿策略,抑制了风载荷干扰对控制系统的不利影响;利用描述函数法分析了包含摩擦特性的非线性系统闭环特性,说明这种控制策略可以避免极限环的产生.最后,开展了数学仿真和现场试验.在一深空探测系统上的应用结果显示,提出的控制策略超调比原产品减少了34％,抗击阵风干扰能力提高了60％,跟踪精度提高显著.得到的结果表明设计的控制策略提高了系统抗风干扰的能力.
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