Research On The Control Technic Of Rotorcraft-UAV Used For PAPI Verification

PAPI(precision approach path indicator) system is of great significance for the safety of civil aviation airplane. For now, the verification is carried out through a civil aviation airplane, which is of low accuracy, high cost and complicated procedure. A PAPI verification system based on rotorcraft UAV(Unmanned Aerial Vehicle) has been designed. The control algorithm, method of precision position and altitude control, way of improving the stability and capacity of disturbance resistance of the rotorcraft UAV were mainly studied.Firstly, the PAPI verification system based on rotorcraft UAV has been designed. Based on the analysis of the civil aviation standards and specification of the angle error to PAPI system, the control precision index of the UAV was proposed.Secondly, according to the stable control requirement of the rotorcraft UAV for PAPI verification mission, the attitude and position control algorithm of the UAV has been studied. The dynamic of the UAV and its Matlab/Simulink simulation model have been established. The control of the UAV based on sliding mode algorithm has been studied. In view of the high frequency chattering phenomenon of the classical sliding mode control algorithm, an improved sliding mode control algorithm based on the nonlinear energy function was proposed. The attitude and position dual closed-loop controller of the UAV based on improved sliding mode algorithm has been designed, and then the simulation experiments have been carried out. The simulation results verify the effectiveness of the designed improved sliding mode controller for the UAV.Thirdly, according to the precision position and altitude control requirement of the UAV for PAPI verification mission, position and altitude control methods based on multi-sensor fusion were studied. To achieve precision position and altitude control of the UAV in the airport environment, a multi-sensor fusion state estimator of the vehicle based on Improved UKF(Unscented Kalman Filter) has been designed, and the related experiments have been carried out. The results show that the designed multi-sensor fusion estimator based on Improved UKF can realize accurate position and altitude control of the vehicle, and meet the requirements of proposed index of the system.Finally, considering that the wind disturbance factor in the airport, the methods of improving the vehicle's stability and capacity of disturbance resistance were studied. In view of the disadvantage of rotor speed open loop control in classical rotorcraft UAV control system, a rotor speed senorless control subsystem based on improved sliding mode observer has been designed. Meanwhile, a dynamic disturbance parameter estimator based on disturbance observing has been designed. At the same time, the hardware and software platform of the system has been established. The practical flight control experiments of the UAV have been done. The results show that the performance of designed UAV can satisfy the index requirement of the vehicle for PAPI verification mission.