Modeling And Attitude Stabilization Control Of Tilt Tri-Rotor UAV

With the rapid development of sensor technology and autonomous control approach,unmanned aerial vehicles(UAVs)have become the strategic commanding points in military and civilian high-tech fields in the world and gained extensive attention and sustained research in recent years.With both efficient cruise and vertical take-off and landing(VTOL)capability,the research on tilt-rotor UAVs has been fierce competition among countries all over the world.Based on the dynamic modeling of the tilt tri-rotor UAV,the research on modeling and attitude stabilization control in multi-rotor mode as well as in transition mode are carried out in this thesis.The main contents and contributions are summarized as follows:(1)Kinematic analysis of tilt tri-rotor UAVThe structure and working principle of the tilt rotor UAV system are analyzed.The advantages of the tilt tri-rotor UAV configuration are compared with that of the double-rotor and four-rotor configurations.The typical mission profile is described in detail.The mathematic model and kinematic mode transition process are established.(2)The dynamic modeling of tilt tri-rotor UAV and parameters identificationBased on the six-degree-of-freedom(6 DOF)kinematics model and the actual force and moments analysis of the tilt tri-rotor UAV,the dynamics model is established,including multi-rotor model,fixed wing model and coupling effect between each other,after which the model parameters are identified initially.(3)Attitude stabilization control of tilt tri-rotor UAVAiming at the stability problem of attitude control in multi-rotor mode,the causes of the attitude instability are analyzed and a dynamic allocation based attitude stabilization algorithm is proposed.It includes the dynamic allocation of optimal design and the dynamic allocation based on tilt angle feedback.Based on Matlab / Simulink,numerical simulation model is built to verify the feasibility and effectiveness of the attitude control system based on dynamic allocation algorithm.(4)Experimental implement of the tilt tri-rotor UAVA large quantity of flight tests are implemented towards the designed tilt tri-rotor aircraft platform,including the stable flight test,the disturbance rejection test and aggressive maneuver test in multi-rotor mode.Based on the stable performance in the multi-rotor mode,the flight mode transition attempts are carried out with the tilt rotors front transition and transition back respectively.The whole autonomous VTOL flight is presented finally and the results verify the feasibility of the attitude stabilization control algorithm proposed in this thesis.