共轴八旋翼无人飞行器的偏航静态抗饱和补偿控制

Static Anti-windup Compensation Control of Yaw Movement for a Coaxial Eight-Rotor UAV

  • 摘要: 设计了一种共轴八旋翼无人飞行器,与四旋翼飞行器相比,其具有更大的驱动能力、更强的带载能力和一定的冗余能力.首先,建立了飞行器的动力学模型.针对共轴八旋翼飞行器偏航运动能力比俯仰、滚转运动能力弱,偏航容易出现执行器饱和现象的问题,从实际工程出发提出了基于线性自抗扰控制器的静态抗饱和补偿器.线性自抗扰算法易于工程调节,能够实时估计与补偿外界扰动.静态抗饱和补偿器不增加系统阶次,有效抑制偏航执行器饱和.利用李亚普诺夫稳定理论证明了基于线性自抗扰控制器的静态抗饱和偏航控制系统的稳定性.最后,通过共轴八旋翼飞行器的仿真实验与原型机比较实验验证了算法的有效性与鲁棒性.原型机实验结果表明:在室内固定干扰下,执行器退出饱和的最长时间约为4 s,偏航角误差收敛到±0.085 rad;在室外变干扰下,执行器退出饱和的最长时间约为9 s,偏航角误差收敛到±0.127 rad.基于线性自抗扰控制器的静态抗饱和补偿器在外界干扰情况下能够有效地抑制执行器饱和,具有良好的偏航控制性能与强鲁棒性.

     

    Abstract: A coaxial eight-rotor unmanned aerial vehicle (UAV) with higher drive capability, greater payload capacity and damage tolerance than a quad-rotor UAV is developed. Firstly, the UAV dynamic model is set up. The actuator saturation tends to occur in the yaw movement of the coaxial eight-rotor UAV, for the reason that the yaw movement is much weaker than the pitch movement and roll movement in the coaxial eight-rotor UAV. For this problem, a static anti-windup compensator based on linear active disturbance rejection controller (LADRC) is proposed from the view point of practical engineering. LADRC is easy to be adjusted in engineering and able to estimate and compensate external disturbances in real time. The static anti-windup compensator can prevent actuator saturation in the yaw movement without increasing the system order. Then, the stability of the yaw control system with static anti-windup compensator based on LADRC is proved based on Lyapunov stability theory. Finally, the validity and robustness of the algorithm are verified via numerical simulations and coaxial eight-rotor prototype experiments. Experimental results indicate that the yaw control system with static anti-windup compensator based on LADRC spends 4 s to exit saturation for the longest time with yaw angle error limited to ± 0.085 rad indoors in the case of constant disturbances, and it spends 9 s to exit saturation for the longest time with yaw angle error limited to ± 0.127 rad outdoors in the case of varied disturbances. The static anti-windup compensator based on LADRC can effectively prevent actuator saturation with accurate yaw control and strong robustness for the coaxial eight-rotor UAV in the presence of external disturbances.

     

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