  During operation, aerial manipulation systems are affected by various
disturbances. Among them is a gravitational torque caused by the weight of the
robotic arm. Common propeller-based actuation is ineffective against such
disturbances because of possible overheating and high power consumption. To
overcome this issue, in this paper we propose a winchbased actuation for the
crane-stationed cable-suspended aerial manipulator. Three winch-controlled
suspension rigging cables produce a desired cable tension distribution to
generate a wrench that reduces the effect of gravitational torque. In order to
coordinate the robotic arm and the winch-based actuation, a model-based
hierarchical whole-body controller is adapted. It resolves two tasks: keeping
the robotic arm end-effector at the desired pose and shifting the system center
of mass in the location with zero gravitational torque. The performance of the
introduced actuation system as well as control strategy is validated through
experimental studies.
