Design And Verification Of Flight Control Law For Tilt Quadrotor

Tilt quadrotor unmanned aerial vehicle, which is called TQR for short, is a kind of new configuration aircraft with both features of quadrotor and fixed-wing aircraft. Combined various advantages of both quadrotor and fixed-wing aircraft, its flight envelope is expanded and its flight range and endurance are increased. It can hover or fly to any direction as quadrotor and can do long distances flight in high speed as fixed-wing aircraft. But as one kind of tilt rotor, its flight control problem is still key point and difficulty in research at home and abroad.Based on the analysis of research results and flight control solution of similar aircraft at home and abroad, some analysis and exploration was made aimed at own unmanned aerial vehicle developed by our research group.Firstly, through characteristics analysis of TQR, the six degrees of freedom movement equation of the TQR was established and the aerodynamic force expression of wings, body and control surfaces was deduced. Thus, the flight simulation model was established in the Matlab/Simulink environment and trim calculation was conducted by control toolbox. The correctness of the model was verified by the characteristic root trends.Secondly, the trim point of the flight mode, quadrotor mode, first rotated mode, second rotated mode and fixed-wing mode, was calculated to make sure control law in each mode can be designed with feedback structure of internal and external loop. The effectiveness of the control law was verified by root locus and time domain curve.Finally, based on the open source APM flight control hardware and software foundation, the flight control system of TQR was established in cooperation with research group successfully. Then a prototype was assembled and flight test was made successfully. It turned out that the control laws designed by this paper had good response capabilities, so that it can meet the expected requirements of TQR.