  This paper presents the utilization of advanced methodologies in aerial
manipulation to address meaningful industrial applications and develop
versatile ultrasonic Non-Destructive Testing (NDT) technologies with aerial
robots. The primary objectives of this work are to enable multi-point
measurements through sliding without re-approaching the work surface, and
facilitate the representation of material thickness with B and C scans via
dynamic scanning in arbitrary directions (i.e. omnidirections). To accomplish
these objectives, a payload that can slide in omnidirections (here we call the
omni-sliding payload) is designed for an over-actuated aerial vehicle, ensuring
truly omnidirectional sliding mobility while exerting consistent forces in
contact with a flat work surface. The omni-sliding payload is equipped with an
omniwheel-based active end-effector and an Electro Magnetic Acoustic Transducer
(EMAT). Furthermore, to ensure successful development of the designed payload
and integration with the aerial vehicle, a comprehensive studying on contact
conditions and system dynamics during active sliding is presented, and the
derived system constraints are later used as guidelines for the hardware
development and control setting. The proposed methods are validated through
experiments, encompassing both the wall-sliding task and dynamic scanning for
Ultrasonic Testing (UT), employing the aerial platform - Voliro T.
