Modeling And Control Of Quadrotor With Single-joint Manipulator

The quadrotor is characterized by small size,low cost,vertical takeoff and landing,and slow precise movements,so it has been widely applied in recent years.However,most applications of quadrotor are limited to monitoring,photographing and other “noncontact” application,which cannot contact with the environment or target objects,and this limits the application scope of the rotorcraft to some extent.By carrying a manipulator on the rotorcraft platform,the system can grab,transport and wipe the target object.For the control of aerial manipulator system,it’s necessary to analyze the interaction between the manipulator and rotorcraft platform and establish the dynamic model of the system.After determining the reaction to the rotor platform when the manipulator is mounted and in actuation,corresponding controllers should be designed for the flight mode,manipulator actuation mode and external force on end-effector mode,so as to achieve the stable position control of the aerial manipulator system in various states.Therefore,this paper studies the dynamic modeling and control of a quadrotor with a single-joint manipulator.The research content mainly includes the following points:1、The basic configuration of a single-joint manipulator mounted under the center of mass of the quadrotor is determined.On the basis of establishing the key coordinate system of the aerial manipulator system and obtaining the transformation relations among the coordinate systems,using Newton-Euler method,the displacement,rotational speed and acceleration of the manipulator joint and the end-effector are calculated from the mass center of the quadrotor.The force analysis from the end-effector to the manipulator joint and the mass center of quadrotor is carried out as well.Then the reaction of the manipulator to the quadrotor platform in all conditions is obtained.On this basis,the dynamic model of the aerial manipulator system is established,and the dynamic response of the model is simulated and tested to verify the accuracy of the model.2、Based on the classical PID control algorithm,the position tracking control algorithm for the aerial manipulator system is designed.A cascade control loop is used to control the linear and angular motion of the quadrotor in the outer and inner loop respectively.The kinematics of the manipulator is added to the control system of the aerial manipulator to realize the position control of the manipulator end-effector.The simulation results show that the algorithm can realize the position control of aerial manipulator system in flight mode and manipulator actuation mode.3、 Based on disturbance observer,a robust position tracking controller is designed for the aerial manipulator system.In order to improve the robustness of the control system,the disturbance observer of the system is designed to compensate the reaction of the manipulator and the disturbance of the external force.Simulation results show that the algorithm can improve the performance of control response in action mode and stress mode.4、Based on the model predictive control algorithm,a position tracking controller is designed for the aerial manipulator system.Considering there’s a model of the reaction of the manipulator and the disturbance of the external force,we can implement model predictive control.Simulation results show that the proposed algorithm can achieve system hovering control and trajectory tracking control under large manipulator maneuvering and external force.