固定翼无人机的二阶PID滑模控制方法

Research on Longitudinal Attitude Control of UAV Based on Second Order Sliding Mode

考虑系统参数摄动和外界干扰对固定翼无人机系统性能的影响,对固定翼无人机姿态角和飞行速度精确跟踪问题进行研究。首先,引入一种非线性干扰观测器来对复合干扰进行精确估计。然后,在干扰观测器的基础上,设计一种自适应二阶PID滑模控制器,将不连续的符号函数隐藏在控制量的一阶导数上,通过积分得到连续的实际控制输入,从而消除切换控制引起的抖振现象,并通过Lyapunov稳定性理论证明了闭环系统的稳定性。仿真结果表明,上述控制方案能保证无人机姿态角和飞行速度控制精度,对参数摄动和外部干扰具有较好的鲁棒性。

Considering the influence of system parameter perturbation and external disturbance on the performance of fixed-wing UAV system,the attitude tracking and flying speed tracking of fixed-wing UAV were studied.First,a nonlinear disturbance observer was introduced to accurately estimate the composite interference.Then,on the basis of the disturbance observer,an adaptive second-order PID sliding mode controller was designed to hide the discontinuous sign function on the first derivative of the control volume and obtain the continuous actual control input through integration The chattering caused by the switching control action was eliminated,and the stability of the closed-loop system was proved through the Lyapunov stability theory.The simulation results show that the proposed control scheme can guarantee the accuracy of UAV attitude angle and flight velocity control,and has good robustness to parameter uncertainties and external disturbances.