一种全局稳定的四旋翼无人机移动目标跟踪控制

摘要

针对地面目标机动不确定和风扰动条件下的四旋翼无人机目标跟踪问题,提出了一种全局稳定的控制策略.控制系统分为位置和姿态两个子系统.位置控制部分针对缺少目标与载机的相对速度问题,设计了输出有界的基于观测器的滑模控制器,且其输出能够保证所生成的期望姿态指令有界;设计了基于四元数的姿态控制器,通过增加非线性切换项,加快了动态跟踪速度,并得到了整个位置-姿态系统的稳定性证明.建立了风扰动模型,进行了目标机动情况下的跟踪飞行仿真,得到了满意的跟踪效果.%For tracking the ground target with unknown maneuvering under gust disturbance,a global stable control policy is proposed for quad-rotor UAV.The control system is divided into position and attitude subsystems.In position subsystem,to the problem of no relative velocity measurement between the target and UAV,a bounded-output sliding mode position controller with observer is designed,which command outputs are in the specified range.The corresponding quaternion attitude controller is designed by using nonlinear switch term to achieve fast convergence.Therefore,the global stability property of the whole position-attitude system is achieved.Finally,the gust is modeled and the simulations of maneuvering target tracking missions show satisfactory tracking performance even in the wind field.