Project Sahabot

The Team

Ralf Möller

In cooperation with

The Purpose

Sahabot 2, as its predecessor Sahabot was built for a specific experiment involving the navigation behavior of the desert ant Cataglyphis. It is being used in a series of experiments performed in the Tunesian part of the Sahara desert in August 1997 in the same area where ethologists collect data on the real Cataglyphis.

Unlike the first Sahabot, Sahabot 2 will not only use its polarized light compass to perform dead reckoning experiments in the open desert, but also use an onboard panoramic video camera to perform visual piloting.

The Collaboration

This is a joint project of the AI Lab and the Neurobiology group at the Zoology Department of our university .
Rosys AG, a swiss robotics company helped with developing and building the robot frame.

Technical Data

physical dimensions
- size: 0.42 x 0.42 x 0.28 meters
- weight: about 8 kg
telemetry and control
- on-board PC104 computer
  - Processor: AMD 586/133MHz, equal to Pentium 75 MHz
  - Memory: 20 MB RAM, 3MB SSD, 1.4GB harddisk, 1.44MB floppy drive
  - Interfaces: 8 analog inputs, 16 digital I/0, 4 RS 232 ports, 1 bidirectional parallel port, keyboard interface, ethernet, PCMCIA slot
  - Display: VGA/LCD card
- on-board Intel 196KD 16bit, 20MHz microcontroller for low level sensor/actuator processing
- communication: radio modem (9600 bits/s) for telemetry to offboard laptop computer
actuators
- two 27 Watt DC motors, 35:1 reduction gear (can be replaced with two optional 75 Watt motors)
- 4 propulsed wheels, differential steering (option of replacing two of these wheels with freely spinning caster wheels)
sensors
- 360 degree panoramic digital camera with conical mirror
- 10 ambient light sensors
- 6 UV polarized light sensors
- electronic compass
- temperature sensors
power
- two 12V batteries, rated at 3.2 Ah
- four fans for temperature control

The Pictures

Figure 1: Side view of Sahabot 2.

Figure 2: Front view. On the side of the front cover: V/A paner meters for the accumulators. Tall structure in the middle: panoramic camera with conical mirror.

Figure 3: Close-up of panoramic camera with 360 degree conical mirror.

Figure 4: Top view of robot with access hatches open.

Figure 5: Top view of the polarized light sensor array, the heart of the polarized light compass; contains three sensor pairs adjusted at 0, 60, 120 degrees (this sensor array is mounted on the back of the robot).

Figure 6: One of the ambient light sensors that are part of the polarized light compass (one of these is mounted on each side of the robot).

Send questions and remarks to <lambri@ifi.unizh.ch>, last update: Oct 12, 2000