基于等效滑模控制法的四旋翼无人机自抗扰控制器设计

Design of active disturbance rejection controller for quadrotor unmanned aerial vehicle based on equivalent sliding-mode control method

针对带有扰动及不确定性的四旋翼无人机的稳定性问题,提出一种基于等效滑模控制法的自抗扰控制器.首先根据机体坐标系和地面坐标系的转化,结合牛顿第二定律和牛顿−欧拉公式,构造无人机的动力学模型.然后设计拓展状态观测器,用来恢复系统状态及对系统所有扰动和不确定性估计,以实现误差快速收敛和提高估计精度.基于自抗扰控制器提出等效滑模控制器的概念,将控制输出分成等效控制项和切换鲁棒控制项,再与非奇异终端滑模控制相结合,避免奇异问题.通过李雅普诺夫稳定性理论证明,设计的自抗扰控制器可以实现系统渐近稳定.数值仿真例子验证了抗扰动性能和鲁棒性.

An active disturbance rejection controller(ADRC)based on equivalent sliding-mode control method was proposed to solve the stability problem of quadrotor unmanned aerial vehicle(UAV)with disturbances and uncertainties.According to the transformation of the body coordinate system and ground coordinate system,combined with Newton's second law and Newton-Euler formula,the dynamic model of UAV was constructed.An extended state observer was designed to restore the state of the system and estimate all disturbances and uncertainties of the system,in order to achieve rapid error convergence and improve estimation accuracy.Based on the ADRC,the concept of an equivalent sliding-mode controller was proposed,and the control output was divided into the equivalent control term and the switching robust control term.Combined with the non-singular terminal sliding-mode control,the singular problem was avoided.Through the Lyapunov stability theory,it is proved that the designed ADRC can achieve system asymptotic stability.Finally,the active disturbance rejection performance and robustness were verified by a numerical simulation example.