Experimental vibration analysis and development of the dynamic model of a uav for aerial manipulation

In the near future, aerial manipulators will be employed in important field applications, such as inspection and maintenance of bridges, tall buildings, wind farms, and offshore and nuclear plants, and search and rescue or structure assembly in hazardous environments. Unfortunately, the precision of aerial manipulators is seriously affected by the dynamic interaction between the Unmanned Aerial Vehicle (UAV) and the robot manipulator. Indeed, on the one hand, the manipulator transfers forces and torques to the UAV, which affect the UAV position and attitude. On the other hand, the UAV induces undesired vibrations on the manipulator. In this paper, first, Experimental Modal Analysis (EMA) has been used to find the experimental vibration modes of a heavy payload UAV. Then, simplified Mass-Spring-Damper (MSD) dynamic models of the UAV have been proposed, to model the most relevant experimental modes of vibration. Finally, a simple 3-Degrees-of-Freedom (3-DOFs) MSD model has been proposed to model the whole system, which eigenfrequencies and vibration modes are in good agreement with the experimental data. The developed model has been used to simulate the system response in the real scenario of a sudden variation in the lift force due to turbulence.