In order to reduce the effects of parameter variations and complex environment disturbances on the altitude control of parawing UAVs (unmanned aerial vehicles),an altitude control strategy based on LADRC (linear active disturbance rejection control) was studied.An eight degree of freedom model of a parawing UAV was built,and the wind and rain models were introduced for the accurate simulation of real flight environments.Based on the features of LADRC,the whole control structure was determined.As a result,the internal and external disturbances were estimated by using linear extended state observer and compensated real-timely by the feedback control law.Flight simulation experiments under various disturbance conditions were conducted.Simulation results show that the altitude control method based on LADRC can not only accurately estimate and compensate the internal/external disturbances but also implement precise altitude control.Compared with standard PID controller,the LADRC controller has better robustness and disturbance rejection ability.%针对伞翼无人机参数不确定性和复杂环境干扰敏感的问题,提出一种伞翼无人机线性自抗扰(Linear Active Disturbance Rejection Control,LADRC)高度控制方法.建立伞翼无人机8自由度飞行动力学模型,并引入风场和降雨模型以更加准确地模拟真实飞行环境.基于LADRC确定总体控制架构,设计线性扩张状态观测器对所有扰动进行估计,并引入误差反馈率在控制中实时补偿.使用该控制方法在多种扰动工况下进行伞翼无人机高度控制仿真实验.仿真结果表明,基于LADRC的高度控制方法能够有效克服内扰和外扰的影响,实现高精度高度控制;与传统PID控制效果相比,LADRC控制器具有更好的抗扰能力和鲁棒性.
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