基于非线性干扰观测器的四旋翼非奇异快速终端滑模控制

Nonsingular Fast Terminal Sliding Mode Control Based on Nonlinear Disturbance Observer for a Quadrotor

针对存在系统不确定性和外部干扰的四旋翼飞行器,提出了一种基于非线性干扰观测器(Nonlinear disturbance observer,NDO)的非奇异快速终端滑模控制(Nonsingular fast terminal sliding mode control,NFTSMC)策略。首先,利用NDO估计系统不确定性和外部干扰的实际值。然后,设计基于趋近律的NFTSM控制器用于姿态子系统(内环),该控制策略能够保证欧拉角的快速收敛以及姿态子系统的稳定性。此外,在位置子系统(外环)中采用NFTSMC与反演技术相结合的策略,保证了位置子系统的跟踪性能。最后,通过对比仿真结果表明,该方法具有更好的轨迹跟踪性能,且优于传统滑模和积分反演滑模控制的效果。

Given external disturbances and system uncertainties,a nonsingular fast terminal sliding mode control(NFTSMC)method integrated a nonlinear disturbance observer(NDO)is put forward for quadrotor aircraft.First,a NDO is proposed to estimate the actual values of uncertainties and disturbances.Second,the NFTSM controller based on the reaching law is designed for the attitude subsystem(inner loop),and the control strategy can ensure Euler angles’fast convergence and stability of the attitude subsystem.Moreover,the NFTSMC strategy combined with backstepping is proposed for the position subsystem(outer loop),which can ensure subsystem tracking performance.Finally,comparative simulations show the trajectory tracking performance of the proposed method is superior to that of the traditional sliding mode control(SMC)and the SM integral backstepping control under uncertainties and disturbances.