Aasimon.org Wiki

Date: November 14th 2008
Duration of activity: 8-13
Participants: Kasper, Bent and Johnny

Make a robot that drives from one point to another, using (x,y) coordinates, while avoiding obstacles.

• Build a car fit for navigation.
• Find out how to use the tacho counter.
• Find out how to use the compass.
• Find out how to use the two navigator classes, and decide on which one to use.
• Calibrate the navigator, using the wheel size and track width.
• Write and test navigation program.

Marvin

CompassNavigator¹⁾ TachoNavigator²⁾

As a starting point we measured the wheel diameter and the distance between the center of the two wheels. These distances are measured in cm and the values are parameters of the function TachoNavigator(). To calibrate the first parameter, wheelDiameter, we tested Marvin to travel 2.00m on a straight line. If he goes beyond this distance, the program uses too many rotations, which indicates the wheelDiameter is set too small compared to reality. After some tests the wheeldiamter was set to 6.9cm. Thereafter we can calibrate the distance between the center of each wheel by choosing Marvin to make N rotations around its own axis. We decided to make 4 rotations and experimenting with the parameter, trackWidth, while keeping wheelDiameter constant. The calibrated value was set to 17.68cm.