Research On Flight Control Of Quadrotor Loaded UAV

Quadrodor Unmanned Aerial Vehicles(UAVs)are small crafts capable of vertical take-off and landing(VTOL)and hovering in the sky.It has many advantages that other aircraft can hardly compare to,such as its small scale,light weight,flexibility,excellent performance.Because of UAV superiority of convenience,speed,low-cost and carrying capacity,the flight control of the quadrotor UAV has become a hotspot in today's research,but there is less research on the control of the quadrotor load UAV.This paper focuses on the loading function of the quadrotor UAV.By designing suitable control algorithms and strategies,the quadrotor load UAV can smoothly and accurately complete the unloading task.The main research contents of this article include as follows.Firstly,in this paper,based on Euler-Lagrange dynamic theory,a classic m odel of a quad-rotor UAV is established,from which the conversion relations of inertial coordinate system and body coordinate system was derived.Then,so me improvements were made over the classic model to further research quadrot or load drones of which the dynamical model was built up during the research process.By improving the existing classical quad-rotor UAV mathematical model,the dynamic model of a quadrotor load UAV is established.Secondly,this paper introduces and analyses the theoretical principle of the classic active disturbance rejection control(ADRC)technique of quad-rotor UAVs,and improves the combination of nonlinear error feedback of the classic ADRC structure,to design a optimized nonlinear error feedback function by which the chattering of control volume of quadrotor UAVs can be better reduced.Moreover,by using the improved ADRC algorithm,a simulation experiment of fixed-point flight was conducted to compare to the result of the simulation experiment applying the classic ADRC algorithm.It's known from experimental results that the improved ADRC algorithm has its prominent excellent properties.Finally,This paper further studies the flight control of quadrotor load unmanned aerial vehicles.In order to better control the position and attitude of the quadrotor load UAV,a double loop control structure with inner and outer loop is designed to improve the technique of the UAV.An adaptive non-singular terminal sliding mode was used in the outer loop of the control structure,approaching to control the position subsystem of the UAV.While an inner loop adapts the improved ADRC algorithm to control the attitude subsystem of the UAV.In order to ensure the stability of the innerand outer loop control,the tracking differentiator in the improved auto disturbance rejection controller has been further improved,and a nonlinear tracking differentiator based on the combination of Sigmoid function and terminal attractor The system has faster response and stronger resistance.The experimental comparisons of the fixed-point flight and trajectory tracking algorithms of the quad-rotor load drone proves that the control algorithm designed in this paper possesses good robustness and accuracy.