S-bot mobile robot

The s-bot is a small differential wheeled mobile robot developed at the LIS at the EPFL in Lausanne, Switzerland between 2001 and 2004. Targeted to swarm robotics, a field of artificial intelligence, it was developed within the Swarm-bots project, a Future and Emerging Technologies project coordinated by Prof. Marco Dorigo. Built by a small team of engineers of the group of Prof. Dario Floreano and with the help of student projects, it is considered at the time of completion as one of the most complex and featured robots ever for its size. The s-bot was ranked on position 39 in the list of “The 50 Best Robots Ever” by the Wired magazine in 2006.

Purpose and use of the s-bot

This is a research robot, aimed at studying teamwork and inter-robot communication. To do this, the s-bots have several special abilities:

Using their gripper, they can connect. Then they can, for instance, pass over gap and steps where a single robot would have failed.
Using their integrated force sensor, they can coordinate to retrieve an object to a certain location without the use of explicit communication. This is the way ants bring preys to the nest.

Of course, all other sensors and actuators, also found on other robots, can be used to do teamwork such as food foraging.

Technical details

General

12 cm diameter
15 cm height
660 g
2 LiIon batteries
1 hour autonomy moving

Control

400 MHz custom XScale CPU board, 64 MB of RAM, 32 MB of flash memory
12 distributed PIC microcontroller for low-level handling
Custom Linux port running Familiar
Wi-Fi

[Image:Sbot mobile robot passing step.jpeg|thumb|Image of the s-bot mobile robot climbing a step in the swarm-bot configuration.]

Actuators

2 treels
turret rotation
rigid gripper elevation
rigid gripper
3 axis side arm
side arm gripper

Sensors

15 infrared sensors around the turret
4 infrared sensors below the robot
position sensors on all degrees of freedom except gripper
force and speed sensors on all major degrees of freedom
2 humidity sensors
2 temperature sensors
8 ambient light sensors around the turret
4 accelerometers, which allow three-dimensional orientation
1 640×480 camera sensor. Custom optic based on spherical mirror provides omnidirectional vision
4 microphones
2 axis structure deformation sensors
optical barrier in grippers

[Image:Sbot mobile robot by night.jpg|thumb|S-bot by night showing color ring.]

LEDS

8 × RGB Light-emitting diodes around the turret
red Light-emitting diodes in grippers

[Image:Sbot mobile robot passing gap.jpeg|thumb|Several s-bots in swarm-bot configuration passing over a gap.]

Special abilities

S-bots can connect to other s-bots to create a bigger structure known as the swarm-bot. To do so, they attach together using their rigid gripper and ring. An s-bot has sufficient force to lift another one.

Integrated software

The s-bot features a custom Linux port running the Familiar Linux distribution. All sensors and actuators are easily accessible through a simple C API.