IEEE Robotics & Automation Magazine - September 2018 - 45

provides a list of inbuilt APIs to help in the development of
high-level reasoning and behavioral capabilities.
One of the unique capabilities of the Pepper robot is dialog-based interaction, which is crucial for delivering a natural and more gratifying HRI. A dialog-based interaction
system can be easily created using the NAOqi ALDialog and
Qichat modules. These provide various functionalities to
devise and shape natural interaction, such as originating
concepts and topics. The modules also serve as one of the
easiest means to provide input to and command the robot
through natural language.
In addition, the robot is equipped with the Animated
Speech and Expressive Listening modules to display humanlike gestures while speaking or listening. These, combined with
Pepper's 17 articulations, allow the machine to move fluidly in
ways that make it appear more naturally interactive, with the
aim of achieving a high level of human-robot engagement.
As indicated earlier, in the "Hardware Design Outline"
section, Pepper is equipped with various tactile areas, LEDs,
and a tablet. These, combined with its dialog- and animationbased interaction capability, provide a unique capacity to
interact with humans in a multimodal way using speech,
expressive gestures, and a graphical user interface.
Support for Behavioral Autonomy
The Pepper robot has modules for various autonomous
behaviors. It comes with the Autonomous Life module, the
basic awareness capabilities of which keep the robot visibly
active and seemingly alive. The original idea was to show
that the robot is different from any other object by having it
do something simple and appear active. This is also a way for
the robot to demonstrate that it is in the present and ready
to help or interact. It also gives the impression of having its
own personality. For the developers, it is a source of inspiration for developing interesting, engaging, and fun behaviors.
Moreover, the Autonomous Life framework provides the creators with the possibility to further customize a particular
type of advanced autonomy depending on the requirements
and situation. It allows the Activities and Behaviors modules
to be autonomously initiated when their specific Launch
Trigger Conditions are satisfied via situation-assessmentbased events.
Basic Navigation and Manipulation Capabilities
On the software level, Pepper is equipped with modules to
achieve basic navigation and local obstacle-avoidance behavior. In addition, it is possible to use ROS-based modules for
navigation-oriented perception and planning.
Pepper is not designed to manipulate objects as a core
functionality. However, the fact that it is equipped with two
arms, each with a five-fingered hand, and thanks to its appropriate height, the robot can be used to achieve some basic
object handover and tabletop manipulation tasks using
NAOqi and the ROS (thanks to its compatibility with the
ROS and the already established link of NAOqi through the
ROS bridge).

Safety: A Must-Have Feature at Different Levels
Safety is one of the essential features of the Pepper robot,
especially because it is mobile, has a body language, and is
supposed to operate in a human-centered environment and
interact with people in close proximity. The machine is
equipped with a fall manager, a push recovery (balance manager) module, and an inverted pendulum control to stabilize
itself. Thanks to these, Pepper is able to manage its balance
not only during its own dynamic motion (sent by the software
to the motors) but also when external forces are applied to it.
Because of its three-wheel locomotion system and its very low
center of gravity, the machine is designed not to fall as often
as the bipedal NAO robot.
To ensure safety even during Pepper's shutdown process
(started by pressing the chest button), a two-step procedure
has been adopted. First, the robot goes into a relaxed and safe
position and then turns
its motors off. It also has a
stop button at the back. In
The robot's hull is
addition, as described
earlier, the robot has no
constructed of high-quality
sharp edges. If someone
bumps into the machine,
plastic, and many parts
it tries to maintain its balance, moving, if needed,
consist of soft plastics to
to recover from a strong
push. If the robot is pushed
reduce the risk of pinching
hard enough to fall over, it
cuts off all of its motors as
during physical interaction.
it falls softly to the floor.
Most of the weight is in
the base near the wheels, so the upper body is relatively light,
which mitigates a fall.
The ISO 13482 norm, section 5.10 (https://www.iso.org/
obp/ui/#iso:std:iso:13482:ed-1:v1:en), highlights the hazards
due to robot motion and the corresponding safety requirements. The Pepper robot complies with some of these recommendations. For example, it stops before colliding with any
obstacles that are detected more than 1.5 cm away, and it is
equipped with touch reflex, reduced movement speed, blind
zone analysis, and a module to create a local map for safe navigation. Furthermore, to avoid dangerous movements in blind
zones, the arm speed is lessened when moving inside an
unknown zone. The robot is designed to detect a human or
obstacle using anticollision software. Also, the base is too low
(2 cm) to roll over a human foot. Pepper has a travel speed
limit of 2 km/h and an emergency speed limit (push recovery)
of 3.6 km/h.
The machine further complies with some of the inherently
safe design recommendations of ISO 13482 by, for example,
keeping the center of gravity of the personal-care robot low;
ensuring that mechanical resonance effects cannot lead to
instability; keeping the mass of the moving parts, especially
the manipulator, as low as reasonably practicable; and using
materials or structures to reduce impact forces. In addition,
the safety policy also considers having a failsafe system if the
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IEEE ROBOTICS & AUTOMATION MAGAZINE

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IEEE Robotics & Automation Magazine - September 2018

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