IEEE Robotics & Automation Magazine - December 2018 - 14

estimation, localization, and control of unmanned aerial
vehicles; collaborative exploration; and aerial manipulation.
Aerial manipulation was also demonstrated indoors [11].
By contrast, the AEROARMS project (https://aeroarms-
project.eu/) is more focused on aerial manipulation for out-
door application in I&M, and it includes the development of
new aerial robotic manipulators. We selected three use cases
in industrial environments, particularly in oil and gas plants
(see Figure 2):
1) direct contact measurements while flying
2) robotic crawler deployment
3) installation of sensors.
Performing experiments in these plants required previous
extensive outdoor testing in industrial settings using reliable
aerial manipulators able to deal with the more challenging out-
door constraints. The machines required the agility to recover
from wind perturbations, the compliance to absorb unexpect-
ed impacts, the ability to operate under variable lighting condi-
tions, and the capacity to compensate for inaccuracies in
Global Navigation Satellite System (GNSS) positioning.
Solving these inspection use cases in realistic settings
is a difficult problem. We believe the design and creation
of suitable manipulation systems require the follow-
ing developments:
● aerial robotic manipulators able to apply forces for contact
inspection in any direction and also to compensate for
wind disturbances, as well as dual-arm manipulators for
the installation of sensors in complex settings

Figure 2. An HES Wilhelmshaven GmbH (Germany) refinery.

control systems for the aerial manipulators, integrating the
aerial platform and the manipulator
● bilateral teleoperation systems with haptic interfaces and
an appropriate tradeoff between stability and performance
● a reliable outdoor autonomous perception system
● a planning system that considers the dynamic behavior of
the aerial platform and the arm in a closed loop.
These components, along with a new robot for industrial
applications and the lessons learned from it, are examined in
the following sections.
●

Platforms
Aerial manipulators are multibody systems with coupled (aer-
ial platform-manipulator) dynamic behavior that applies
forces to objects. The AEROARMS project includes the mod-
eling and control of propulsion systems [12] and assessment
of the aerodynamic effects when flying very close to the envi-
ronment [13]; this article, however, concentrates on the plat-
form's main design aspects.
Most aerial manipulators [3]-[6] use standard multirotor
platforms, with all of the propellers oriented in the same
direction. They are thus underactuated, with only 4 degrees
of freedom (DoF), and they need to tilt to move or exert
forces in the horizontal plane. Nonconventional multidirec-
tional-thrust platforms with tilted rotors [14] have been
designed, with the ability to direct the total thrust in more
than one direction of the body frame [see Figure 1(a)]; thus,
they are capable of a full six-dimensional (6-D) wrench exer-
tion without tilting. This configuration has been
used in the Tilt-Hex hexarotor platform [Fig-
ure 1(a)] and the AEROX octorotor industrial
platform [Figure 1(b)]. Their characteristics are
shown in Table 1.
Aerial manipulators use mechatronic devices
such as bars, grippers, or multilink arms to reach
the operation point, grasp and manipulate
objects, and exert forces on the environment. The
design of these devices is important because their
movement induces the displacement of the
center of mass (CoM) as well as variation in
moments of inertia, generating disturbance
torques and affecting the dynamics of the aerial
vehicle [4]. To overcome these effects, a new
AEROX arm configuration has been designed.
The arm's weight is compensated for the batteries,

Table 1. The characteristics of the platforms developed in AEROARMS.

14

*

Aerial Manipulator

Size
(m)

Maximum Total
Mass (kg)

Maximum Flight
Time (min)

Arm(s) Configuration-Maximum Reach

Tilt-Hex

1.05

1.8

8

Fixed-bar arm (0.4 m)

AEROX

2

25

15

One 6-DoF arm (1 m)

Dual-arm, stiff joints

1.7

18

20

Two arms, each with 5-DoF; stiff joints (0.6 m)

Dual-arm, compliant joints

1.2

7

12

Two arms, each with 4-DoF; compliant joints (0.5 m)

IEEE ROBOTICS & AUTOMATION MAGAZINE

*

december 2018
https://aeroarms-project.eu/ https://aeroarms-project.eu/
IEEE Robotics & Automation Magazine - December 2018

Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - December 2018
