Towards Grasping Task: System and Control of an Aerial Manipulator

Towards target grasping by an aerial manipulator, an aerial manipulator system composed of a hex-rotor and a 7-DoF (degree of freedom) manipulator is presented, for which a separated control strategy is adopted, that is, the aerial vehicle and the manipulator are controlled separately. The variations of the system CoM (center of mass), inertia matrix caused by the manipulator movement and the corresponding derivatives are used to estimate the disturbing forces and moments on the aerial vehicle exerted by the manipulator. To attenuate the effect of the manipulator disturbance on the flight control performance of hex-rotor, a disturbance compensation H_∞ robust flight controller is designed. The experiment results show that the disturbance compensation H_∞ robust controller can obviously improve the flight performance of the aerial vehicle when the manipulator is moving, comparing with the controller without disturbance compensation. Finally, aerial grasping experiments are conducted to validate the reliability of the proposed aerial manipulator system.