基于LADRC的无人机高精度定高控制

针对复杂气流扰动对无人机（UAV）航迹高度控制的影响，对存在复杂气流扰动下的定高控制策略、控制结构和控制器参数优化展开研究，实现高精度高度控制。基于线性自抗扰控制（LADRC）确定总体控制架构，设计扩张状态观测器（ESO）观测估计纵向高度通道和速度通道中存在的总扰动，在控制中引入扰动补偿，减小扰动对系统输出造成的影响。对UAV在飞行过程中存在的大气紊流扰动或离散突风等风干扰分析其功率谱密度，构造考虑风扰动对高度影响、时域响应特性和稳定裕度的综合目标函数，通过粒子群优化算法得到具有高精度、高抗干扰性能的控制器参数，优化中考虑风干扰的功率谱密度分布，减小了控制器参数设计的保守性。通过与常规比例-积分-微分（PID）控制器控制效果进行对比，说明基于线性自抗扰控制器的纵向高度控制的优异性能。 

Precise height control for UAV based on LADRC

Aimed at solving the impact of sophisticated wind disturbance, research on the control strategy, control structure and parameter optimization design is developed in this paper to realize height control with high precision performance in the longitudinal channel of unmanned aerial vehicle (UAV). First, based on the features of linear active disturbance rejection control (LADRC), the whole control structure is determined, and the probable disturbance from both inside and outside of the system can be estimated using the extended state observer (ESO). As a result, influence of disturbance on the output of the system can be eliminated by introducing this estimated value into the control law. Second, the power spectrum density of the wind turbulence and discrete gust are also analyzed, and a comprehensive fitness function considering impact of wind disturbance on height, characteristics of time domain response and stability margin is constructed, so that controller parameters with high precision and high disturbance-rejection performance can be produced through the particle swarm optimization algorithm to reduce the conservatism of controller parameter design. Finally, the outstanding performance of linear active disturbance rejection controller in the longitude channel of UAV is illustrated through being compared with the regular proportinal-integral-derivative (PID) height controller.