Flight Control Modeling And Control Law Design Of Small Fixed Wing Uav

The small fixed wing UAV is portable,disassemble,and has strong maneuverability.It is suitable for performing diverse tasks and is widely used in civil fields such as fire protection and plant protection;military fields such as security and inspection.Though small fixed wing UAV have a small volume and are susceptible to environmental interference,they have high mobility requirements,so flight control systems need to have a greater impact on flight performance.The thesis conducted research from the aspects of small fixed wing UAV flight control modeling,longitudinal and lateral control loop design,flight control digital simulation,flight controller hardware and software design as well as test verification.According to the structural characteristics and aerodynamic parameters of the small fixed wing UAV,the kinematics and dynamics equations were analyzed,the nonlinear model of the UAV was established as well.The nonlinear model was trimmed and linearized under typical flight conditions to obtain longitudinal and lateral equations of motion.The control law design and flight simulation were done based on the linearized equations of motion.Pitch angle control loop and altitude control loop for UAV longitudinal movement;roll angle control loop,yaw angle control loop as well as lateral distance control loop for horizontal and lateral movement were designed with PID control law.In the attitude angle control,the control structure based on feedforward and angular rate inner loop was adopted to improve the response speed and reduce the system overshoot.Aiming at the problem that traditional PID control is affected by model errors and interference,the sliding mode control method based on the backstepping method and the （?）₁ adaptive control method were used to improve the control effect of the attitude angle loop,which proved to be suitable for improving the antiinterference ability of the UAV.This thesis designed and developed the graphical user interface for digital simulation.The simulation of UAV flight mission was carried out,and the accuracy of the flight simulation system was proved according to the simulation results of waypoint flight.The software and hardware of the flight controller was design.Based on the developed flight controller,the actual flight verification was carried out.It was verified that the digital simulation has guiding significance for the practical application of the algorithm.