Adaptive Control And Trajectory Planning For The Quadrotor Slung-Payload Aerial Transportation System

In recent years,quadrotor unmanned aerial vehicle(UAV)has been widely used in various fields because of its advantages of high stability,convenient control,vertical taking-off and landing.The quadrotor UAV itself is underactuated,and the introduc-tion of the slung payload makes the control of the whole system a very challenging problem.On the one hand,the quadrotor slung-payload aerial transportation system includes eight degrees of freedom:three translational motion of the quadrotor,three rotational motion of the quadrotor and two swing motion of the payload.However,the whole system has only four independent control inputs provided by four propellers.And the motion of the slung payload can only be adjusted by the motion of the quadro-tor UAV,which further bring more underacuated properties and state coupling issue for the control development.On the other hand,the swing of the slung payload will affect stability of the quadrotor.In order to meet the control requirements for the quadrotor slung-payload aerial transportation system,this thesis has introduced some new control design methodologies.The main results of this thesis are listed as follows:1.In this thesis,a two-dimensional dynamic model of the quadrotor slung-payload aerial transportation system is established by using the Euler-Lagrange method.The dynamic properties of the longitudinal channel and the altitude channel are comprehen-sively considered and utilized for the subsequent control development.2.Based on the established two-dimensional dynamic model of the quadrotor slung-payload aerial transportation system,the effects of air drag forces on the quadro-tor UAV are investigated.A new adaptive control strategy based on the energy shaping method is designed for the underacuated and unmodeling dynamics of the whole sys-tem.The energy shaping method is used to introduce the swing angle information into the control input to deal with the state coupling issue,and the neural network is used to compensate the unmodeling dynamics of the system.The stability of the closed-loop system is proved via the Lyapunov based stability analysis.Finally,numerical simu-lation and real-time flight experiments verify that the control strategy proposed in this thesis has achieved good control performance.3.In order to drive the quadrotor to its destination accurately and suppress the swing motion of the slung payload effectively,an on-line trajectory planning method is proposed in this thesis.To deal with the unknown external disturbances,the desired trajectory of the quadrotor UAV is divided into two parts:the positioning trajectory part and the disturbance rejection trajectory part.The positioning trajectory part can be set in advance to guide the UAV to reach the target position,and the disturbance rejection trajectory part can compensate the unknown disturbance based on the reinforcement learning strategy and suppress swing motion of the payload at the same time.Lyapunov based stability analysis is employed to prove the stability of the system.Finally,exper-iments are performed to verify the effectiveness of the proposed trajectory generation method and its robustness to external disturbances and variation of the mass of the slung payload.