The Design, Modeling And Control Of The Manipulator System For Rotary-wing Unmanned Aerial Vehicle

Because the R-UAV(Rotary-wing Unmanned Aerial Vehicle) has the ability to hover on a fixed point, cruise at low-altitude and low speed, vertical takeoff and landing, which abilities that other aerial vehicles do not possess. And after the development of more than a decade, R-UAVs have been widely utilized in surveillance, patrol and other fields. But these applications are mainly focused on the observation and perception of the environment. The combination of R-UAV and manipulator to become an Aerial Manipulator is a new design concept proposed recently. The aerial manipulator is able to extend the human hand to the air to complete tasks that many other robots are unable to complete, thus expands the original application fields of the manipulator. Aerial manipulators are particularly suitable to work remotely controlled or autonomously in harsh environments which are difficult for human beings to reach. This paper focuses on the task of cutting off of power transmission cable which is necessary for the maintenance of power transmission line, and desires to ensure the security of the power grid through the design and implementation of the aerial manipulator and its application of cutting off of the damaged power transmission cables in remote mountainous areas, and thus to verify the control method for the R-UAV’s manipulator.The paper first analyzes the current developments of aerial manipulators inland and abroad. Then a manipulator is designed according to the payload limit of the R-UAV and the requirements of the cutting off of the power transmission cable. And a hydraulic based drive system for the manipulator is proposed to ensure the security and the shearing force during the cutting off operation. The effectiveness of this manipulator is verified through the actual cutting off of a power transmission cable. A kinematics model of the manipulator is established based on the D-H method, and the dynamic equations of the manipulator are established based the Lagrange equation. The kinematic model and the dynamic equations serve as the foundation of the simulation analysis and the design of the controller. In the control design part, in order to address the mutual coupling problem between the manipulator and the R-UAV, a method of taking the interactive force / torque as a disturbance which is incorporated in the controller is proposed, and a H∞ based robust controller is established to tackle the disturbance rejection problem, thus to ensure the safety of the flight during aerial manipulation. Simulation results indicate that the proposed robust control method can effectively address the impact of the mutual coupling effects. Based on the needs for the manipulator’s trajectory planning during manipulation, inverse kinematics models from the end-effector to each joints of the manipulator are established, as well as the corresponding trajectory planning method. The planning method is validated through a linear operation trajectory.This paper has completed the structural design and the electrical integration of the manipulator, the establishment of the kinematics and dynamics model, and designed a robust control design method as well as a trajectory planning method. This paper has completed simulation of the proposed method and its experimental verification, and finally gave the simulation and experimental conclusions.