Research And Realization Of Landing Control Of Small Tilt-rotor UAV

In this paper,a tilt rotor UAV is studied.This paper mainly studies the whole landing process: establishing the dynamic model.The control system is designed for the transition stage and helicopter mode.As a new type of aircraft,tilt rotor aircraft has the characteristics of both helicopter and fixed wing aircraft.It can take off and land vertically and fly at high speed.The whole landing process is from fixed wing mode to helicopter mode after transition mode.When the tiltrotor is in the transition mode,the whole system will show more nonlinear and strong coupling characteristics with the nacelle tilting.This makes the control of the whole landing process more complex.When landing in helicopter mode,the existence of external interference also affects the stability of the system.First of all,according to the motion characteristics of tilt rotor aircraft,the nonlinear kinematic dynamic model of tilt rotor aircraft is established by using the split method,and then the aerodynamic analysis of each component shows that the model is reasonable.Then,in order to make the tilt rotor aircraft pass through the transition phase safely and stably.Under the reasonable assumption,the longitudinal control problem in the transition phase is mainly considered.The control scheme in the transition phase is designed reasonably.The control law of the position system and the pitch attitude system of the tilt rotor aircraft is designed by using the strong robustness of the sliding mode control.Then,according to the six degree of freedom model of the tilt rotor aircraft,a terminal sliding mode method is proposed to control the trajectory of its helicopter landing mode,and a double loop position and attitude control system is designed.A new adaptive disturbance observer is introduced to accurately estimate the disturbance of the system and improve the accuracy of the control law.The effectiveness of the this system can be verified by experiment.Finally,in order to test the practical application effect of the algorithm designed in this paper,the altitude control verification experiment in the transition phase and the helicopter mode landing verification experiment in the presence of external interferenceare carried out under the environment of quanser semi physical experiment platform.The experimental results show that the control effect of the designed control system is good.It also shows that the algorithm in this paper has some engineering application value.