Research On Longitudinal Control System Of Seated VTOL UAV

VTOL fix-wing UAV has more advantages than the traditional.It can not only take-off and landing vertically like the helicopter,but also travel in high speed and long voyage as fixed-wing airplane.And inherit the advantages while overcoming the disadvantage of the traditional fixed-wing UAV VTOL.Moreover,it is also capable to fit certain circumstances to fulfil specific assignments like the traditional UVA.This paper mainly focuses on the research on the VTOL with vector tension.The vector motor fixing seat,control the motor speed to change the lag and control vector motor seat of the horizontal and vertical tilt angle,is installed at the top of the fuselage in order to change the direction of motor pull to control the attitude of pitch and yaw.Under this control mode,aircraft flight control at a low speed is almost constant and it greatly improve the flexibility of low-speed case flight control system.And the direct force control simplify the system model which benefit the system simulation and analysis.The ailerons,lead to roll control by servo,are arranged at the bottom of the wing.But Tail-sitter VTOL UAV will appear the singular point when the angel of pitch direction change over 90 degrees.This paper provides a way to change the order of rotation for attitude angle of singular points.The results show that this method can be well applied to the attitude solution of the VTOL UAV.The yaw angle is corrected by HMC5883 L while MS5611 sensor to the height loop.The fuzzy PID controller,which has stronger anti disturbance and robustness,is used to control the aircraft longitudinal attitude.And the cascade PID controller is adopted to control the roll,yaw and height.Build the dynamic model of Tail-sitter VTOL UAV and analyze the longitudinal stability of system model in process of hovering and tilting.Fuzzy PID controller and related membership function is designed for correction and control.Program the PC software based on Delphi to set the parameters of PID and to display the attitude angle.The design realizes the process of take-off,hovering,flat flight,landing.And it is improved according to the actual requirement which lead to good operability and adaptability.It can be widely used in some special areas and it has high research significance.