IEEE Robotics & Automation Magazine - September 2018 - 44

Sensors and Network
The Pepper robot has a range of sensors to allow it to perceive
objects and humans in its surroundings and help the software
components make sense of everything. These are illustrated
in Figure 3 and outlined as follows.
● Six-axis inertial measurement unit (IMU) sensor: The
machine is equipped with an IMU composed of a threeaxis gyrometer with an angular speed of ~500 °/s and a
three-axis accelerometer with an acceleration of ~2 g. The
output data enable an estimation of the base speed and attitude (yaw, pitch, and roll). Inside the inertial board, an
algorithm is implemented to compute the base angle from
the accelerometer and gyrometer.
● Microphones: Pepper has four microphones in the head to
provide sound localization. These have a sensitivity of
250 mV/Pa (±3 dB at 1 kHz) and a frequency range of
100 Hz to 10 kHz (−10 dB relative to 1 kHz).
● Cameras and three-dimensional (3-D) sensor: The robot has
two red-green-blue (RGB) cameras at the forehead and

●

Head Tactile Sensor
×3
Microphone
×4

3-D Sensor
×1

RGB Camera
×2

Tactile Screen
×1

mouth positions. The resolution is 2,560 × 1,920 at
1 frame/s or 640 × 480 at 30 frames/s. One 3-D sensor is
located behind the eyes. It provides an image resolution of
up to 320 × 240 at 20 frames/s.
Tactile sensors, bumper sensors, and tablet: There are three
tactile sensors: one in the head and one on top of each of
the hands. The robot also has three bumper sensors, one
on each wheel position. In addition, it has a tablet attached
to its chest.
Laser sensing modules: These are composed of six laser line
actuators (laser line generators) and three sensors. Three
actuators are at the front of the robot to evaluate the
ground before it. The other three are at the robot's lower
base to sense the surroundings. These three sensors are
located at the front and the left and right sides.
Loudspeakers, sonar sensors, and infrared sensors: The Pepper robot is also equipped with two loudspeakers, laterally
placed on the left and the right sides of the head; two sonar
sensors, one in front and one in back; and two infrared
sensors at the base.
Network connectivity support: This includes Ethernet
(1x RJ-45 10/100/1000 Base-T) and Wi-Fi (IEEE 802.11
a/b/g/n; Security: 64/128-b: wired equivalent privacy,
Wi-Fi protected access (WPA)/WPA2). In terms of the
communication protocol among components, RS-485 is
used between the motor/sensor board and the internal
computer, and communications device class-Ethernet control model is used on a universal serial bus cable between
the tablet and the CPU.

Software Features

Hand
Tactile
Sensor
×2
Laser Sensor
×3
Sonar Sensor
×2

Infrared
Sensor
×2

IMU
×1

Bumper
×3
Sensor Positioned at
the Other Side/Back

Laser Actuator
×6

Figure 3. The Pepper robot's sensors. (Image courtesy of
SoftBank Robotics.)

IEEE ROBOTICS & AUTOMATION MAGAZINE

september 2018

Software Development Kits and Documentation
NAOqi is the name of the developed underlying operating
system that runs on Pepper and controls it. NAOqi also provides a programming framework to develop applications on
the robot. It addresses common robotics needs, including
parallelism, resources, synchronization, and events. Different
software development kits are provided to control Pepper and
develop it: Python, C++, Java, JavaScript, and the Robot
Operating System (ROS) Interface (http://wiki.ros.org/
Aldebaran). Updated documentation is maintained online for
developers (http://doc.aldebaran.com). There is also a dedicated developer community (https://developer.softbank
robotics.com) for support and a question-and-answer forum.
Multimodality of Natural Interaction at the Core
As mentioned, the core requirement of the initial B2B scenario
was interaction with humans, and the capacity to perceive
people is one of the main capabilities to achieve this. Therefore,
the Pepper robot is equipped at both the hardware and software
application programming interface (API) levels to provide
good functionality for perceiving humans. The multimodal
perception components are primarily intended to discern people's presence and avoid collisions with the environment during
body movement. The NAOqi's People Perception module

http://wiki.ros.org/Aldebaran http://wiki.ros.org/Aldebaran http://doc.aldebaran.com http://developer.softbankrobotics.com

IEEE Robotics & Automation Magazine - September 2018

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