Research On Control Of Qaudrotor UAV Based On Sliding Mode Active Disturbance Rejection Technology

The quadrotor UAV is characterized by small size and simple structure.It can accomplish tasks that cannot be completed by fixed wings UAV,such as vertical take-off and landing,low-speed flight,and air hovering.Therefore,it is widely used in civil and military fields.In this paper,the quadrotor UAV is used as the research object to design its flight controller.The content includes the following four aspects:(1)The characteristics and working principle of quadrotor is analyzed.Considering the influence of uncertain factors,Newton-Euler equation was used to construct the dynamic model of quadrotor.(2)For the problem of parameter uncertainty and external disturbance of quadrotor UAV,this paper designs a quadrotor UAV controller based on linear ADRC technology.An extended state observer with variable gain is designed to improve the "peak problem" caused by excessive gain.The simulation and experimental results show that the designed controller has better tracking effect and robustness than the traditional cascade PID controller.(3)For the problem of limited estimation ability for linear ADRC controller,a quadrotor flight control strategy combining linear ADRC and sliding mode control is designed.The linear ADRC feedback control rate is improved to the non-singular terminal sliding mode control rate.The total disturbance estimated by the extended state observer is introduced into the design of the sliding surface.The stability of closed-loop control system is proved by Lyapunov method.Experimental and simulation results show that the designed controller has good speed and robustness.(4)Based on the non-singular terminal sliding mode active disturbance rejection control strategy,a fast terminal sliding surface with better response is proposed.In order to solve the problem of slow convergence of non-singular sliding when surface far from the equilibrium point,to achieve global fast convergence,and to further improve the rapidity of the system.To further improve the speed of the system.Aiming at the problem that the sliding mode control rate is vulnerable to external interference at the arrival stage,the adaptive combination approach law is designed to improve the robust performance of the system.Experimental and simulation results show that the designed controller improves the system’s rapidity and robustness and weakens the sliding mode chattering caused by external disturbances.