  This paper presents a static-equilibrium oriented interaction force modeling
and control approach of aerial manipulation employing uni-directional thrust
(UDT) multirotors interacting with variously defined environments. First, a
simplified system model for a quadrotor-based aerial manipulator is introduced
considering parameterized work surfaces under assumptions, and then a range of
meaningful manipulation tasks are utilized to explore the system properties in
a quasi-static equilibrium state. An explicit interaction force model in
relation with the aerial manipulator pose configuration and the environment
parameter is derived from the static equilibrium analysis, based on which
singularity is pointed out. Then a hybrid attitude/force interaction control
strategy is presented to verify the proposed interaction force model, which
involves high gain attitude control and feedforward plus feedback force
control. This paper represents preliminary results. We study the properties of
UDT-based aerial manipulators via specific tasks, and propose a novel framework
for interaction force modeling and control aiming at maximizing the commercial
values of UDT platforms for aerial manipulation purpose.
