Compliant Bimanual Aerial Manipulation: Standard and Long Reach Configurations

The ability of aerial manipulation robots to reach and operate in high altitude workspaces may result of interest in a wide variety of applications and scenarios that nowadays cannot be accessed easily by human operators. Consider for example the installation of sensors in polluted areas, the insulation of leaks in pipe structures, or the corrosion repair in power lines and wind turbines. This paper describes the application of a human-like dual arm aerial manipulator for the inspection of pipe structures, typical of chemical plants, involving the installation and retrieval of sensor devices. The goal is to reduce the time, cost, and risk with respect to conventional solutions conducted by human workers. Two configurations of the aerial robot are considered and compared: the standard, in which the arms are installed at the base of the multirotor, and the long reach configuration in passive pendulum, which extends the effective workspace of the manipulator and increases safety during the operation on flight. The kinematic and dynamic models of both configurations are derived, proposing a unified notation for the equations of motion, and a force/position control scheme that relies on the servo controller and the mechanical joint compliance. The paper also describes a simulation framework used for validating the execution of the aerial manipulation task before the realization of the real experiments, which contributes to reducing the probability of failure. The potential application of the standard and long reach configurations is evaluated in two sensor installation tasks carried out in an indoor testbed.