IEEE Robotics & Automation Magazine - March 2012 - 44

Our group developed several types of ground robotic
vehicles to experiment different traction strategies, control,
localization and navigation algorithms, and measurement
systems (Figure 3). Since the payload needed to carry all
the needed instrumentation was rather high, the adoption
of UAVs was initially excluded because it was considered
useful for specific missions only.
Table 1 summarizes the main ground-prototype robots
developed, their most important features, and several
references where the interested reader could find more
details on each system. With the exception of U-Go, which
was mainly adopted as a mule for several volcanic missions, all other robots were prototypes developed just to
test locomotion architectures or traction strategies that
were useful to the improvement of ROBOVOLC system.
In 2005, we also started a research line for the development of UAVs for volcanic inspections. In particular, the
Volcan Project was initiated in cooperation with INGV,
with the aim of building an autonomous flying system able
to perform gas analysis and sampling and the visual monitoring of volcanic areas. More details concerning this case
could be found in [28] and [29].
ROBOVOLC
ROBOVOLC was the original name of a research project
that was initially funded by the European Commission
from 2000 to 2003. The partnerships included two universities (Universita degli Studi di Catania, Italy, and the
University of Leeds, United Kingdom), two industrial
organizations (Robosoft, France, and BAE Systems, United
Kingdom), and two research organizations that provided
their expertise in volcanology and cartography: INGV,
Italy, and the Institute de Physique du Globe de Paris,
France. A more detailed description of the project with the
latest updates can be found at the project Web site [21]
and in [22] and [23].

The main result of the project was the design, realization,
and testing of the ROBOVOLC platform, as shown in Figure 4. Since the conclusion of the project, the robot has been
continuously updated and tested and is a powerful tool for
the investigation of the adoption of robotics in volcanology.
The Mechanical Platform
ROBOVOLC uses a six-wheeled system with an articulated
chassis. Its dimensions are W 3 L 3 H ¼ 80 cm 3 130 cm 3
180 cm, and its total weight is 350 kg. The robot is skid steering since it is able to rotate by using the different speeds of
the wheels on the right side as well as those on the left. The
wheels are actuated by using six independent dc motors, and
three different types of tires can be chosen depending on the
expected soil. Several tests, also performed on the previously
exposed prototypes, have shown that an articulated chassis
satisfies all requirements and guarantees an adequate
mechanical robustness. The front and rear axles of the robot
have two possible movements: a rotation along the longitudinal axis of the robot, which is only passive, and a second
rotation along the lateral axes (parallel to the rotation axis of
the central wheels), which can be actively controlled by
means of two electric motors. Figure 5 reveals a typical situation on a rocky terrain where the chassis' capability of adapting to the terrain is fundamental. Traction control
algorithms have been developed and tested to maximize the
robot's traction capabilities in different situations [18]-[20].
Power supply is guaranteed by means of four sealed
lead-acid batteries, coupled to form two 24-V units. The
autonomy of the system in typical working conditions has
been tested to be 2 h, while the distances that can be covered are in the order of 3 km.
Control Hardware Architecture
The actual version of the robot is equipped with three PC
boards to manage the wheel speed and traction control, the

*
Table 1. Ground-prototype robots for volcanic exploration developed at the University of Catania.

Wheeleg

Locomotion

Two front legs
(pneumatic) and two
rear wheels (dc
motors)

Six wheels independently
Six wheels independently
actuated by a stepper
actuated by independent
motors inside each wheel
dc motors

Rubber tracks (dc
motors)

Main features

Hybrid locomotion
architectures

Highly adaptive chassis:
Smaller scale prototype of
each pair of wheels is
the ROBOVOLC system
jointed to the other with a
for traction control stratprismatic and rotational
egies test, field-programjoint with variable
mable gate array (FPGA)stiffness
based low-level control
architecture

Two control modalities: teleoperated
and autonomous,
200-kg payload

Dimensions
W3L3H
(cm)

66 3 111 3 40

71 3 75 3 15

20 3 30 3 20

70 3 120 3 110

Weight (kg)

250

References

[15], [16]

[17]

[18]-[20]

[25], [26]

IEEE ROBOTICS & AUTOMATION MAGAZINE

MARCH 2012

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U-Go

Table of Contents for the Digital Edition of IEEE Robotics & Automation Magazine - March 2012