Research On Flight Control Algorithm Of Qball-X4 Quadrotor UAV

With the development of science and technology,the four-rotor UAV plays an important role in both the military field and the civil field by virtue of its small size,low cost,lightness and flexibility.The stability of four-rotor UAV flight control is a core issue,which has very important research significance.The thesis analyzes the domestic and international research status and flight control algorithm research status of quadrotor UAV,establishes the mathematical model of Qball-X4 quadrotor UAV,and designs the controller by LQR control,H_∞control and H₂ control respectively for simulation analysis.A robust H_∞controller and a robust H₂ controller are designed for the uncertainty system of the Qball-X4 quadrotor UAV,which is analyzed and verified by simulation.The main research contents include:Firstly,by analyzing the structure of the four-rotor UAV,the working principle of flight and the transformation of the coordinate system,the nonlinear mathematical model of the Qball-X4 four-rotor UAV is established by Newton-Euler equation.Secondly,the non-linear mathematical model is linearized,the LQR controller,the state feedback H_∞controller and the state feedback H₂ controller are designed,and the simulation model is built using the Matlab/Simulink platform.The analysis of the simulation was conducted under the three conditions of no interference,bounded interference and white noise interference.Finally,a robust H_∞controller and a robust H₂ controller are designed for the uncertainty system of the Qball-X4 quadrotor UAV,and the Matlab/Simulink platform was used for simulation and analysis in the three situations of no interference,bounded interference and white noise interference.The results show that the Qball-X4 quadrotor UAV system can restore the controlled system to equilibrium through LQR control,state feedback H_∞control,and state feedback H₂control.In the presence of bounded disturbances,the state feedback H₂ control and state feedback H_∞control have smaller deviation values than LQR control,where state deviation H_∞control has the smallest deviation value.In the presence of white noise interference,state feedback H₂ control has a smaller oscillation amplitude and better robustness than LQR control and state feedback H_∞control.Compared with the robust H_∞controller,the robust H₂controller has better robustness and faster response speed for the uncertain system of Qball-X4 four rotor UAV under the conditions of no interference,bounded interference and white noise interference.