Dynamic Analysis And Nonlinear Control Design For The Tilt Tri-rotor Unmanned Aerial Vehicle

In recent years,with the improvement of various technologies,different types of rotor Unmanned Aerial Vehicles(UAVs)have been rapid developed.The tilt tri-rotor UAV is a special configuration with the advantages such as vertical take-off and landing.Meanwhile this type of UAV is an underactuated nonlinear system which attracts great attention from reserachers in recent years.This thesis focuses on the dyanmic properties analysis and nonlinear control development for the titl tri-rotor UAV,which contains the nonlinear controllers aiming at the attitude height control and the position control respectively.The Lyapunov based stability analysis is employed to prove the stabiilty of the closed-loop system.Real-time experimental results performed on a hardwarein-loop testbed are utilized validate the performance of the proposed design.The main contents of this thesis includes the following three aspects:1.Due to the special dynamics properties of the tilt tri-rotor UAV,the kinematics model and dynamics model of the UAV's position loop and attitude loop are analyzed respectively.2.It is difficult to measure accurate values of the lift coefficient and anti-torque coefficient during the actual flight.This thesis designs a nonlinear adaptive robust control strategy to complete the UAV's attitude and height control in order to compensate the disturbances and the uncertainty of the parameters.At the same time the asymptotic stability of closed-loop dynamical system is proved based on Lyapunov analysis and Barbala's lemma.The stabilization and anti-disturbance experiments are performed on the hardware-in-loop testbed,which proves the robustness and realizability of the designed controller.3.To solve the problem of the position control of tilt tri-rotor UAV,this thesis optimizes the position dynamics model regarding the negative force generated by tilting rudder as the bounded disturbance,using the position-attitude double-loop control.A nonlinear disturbance observer for the position control and a nonlinear robust control law for the attitude control are designed respectively.In addition the stability of the double closed-loop system is proved.And the circle and rectangular trajectory tracking experiments is completed using the the hardware-in-loop testbed.The results show that the proposed control strategy has achieved good tracking control performance.