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Robot: Rigel

Benny Peter Jørgensen

Here is Rigel

Once a year, there is a robot competition at “Danish Technical University” (DTU) called RoboCup. The first competition was back in 1997. It's an open competition and therefore there always come a few teams from outside DTU. Usually the teams contains students from a university, but there also comes people from outside the educational system. If a team is coming from a university, there is usually no direct financing or helping between there institute and the team. Normally there is from 12 to 20 teams at the contest, but only one of the teams comes from the University Of Southern Denmark (called SDU), which is where I come from. Still the winner of 1997 and 1999, and 3. place in 2000 was teams from SDU. This fact has increase my desire of winning this year.

The main issue of the competition is to follow a white line, through some gates which gives one point each. Several places the line is divided into a easy track and a track with some sort of challenge, giving more points. One of the challenges is to manoeuvre around a wall without the help of the white line. Other challenges is driving along a black line on the dark grey floor, driving straight for a known distance without any line and finally choosing between driving down a ramp or down a staircase with 5 steps. The winner is the team with most points (= gates) and incase more that one team having the same number of points the time counts.

Rigel from the side

The robot that I have build for the purpose of winning, is called “Rigel” after the company that has made both the C-compiler and the main board on my robot. The microcontroller on the main board is the old but strong 80C166. The 80C166 contains a 10 channel 10 bit A/D converter, lot of timers, two 16 bit I/O ports, and a 16 bit RISC kernel with pipeline structure. I use this high power mathematical processor to do a lot of calculations while searching for the line. “Rigel” has a line following sensor with 9 outputs, a home made IR based proximity sensor and a bump sensor. It uses a tacho encoder i to regulate the speed of the motor. This way the speed of “Rigel” is the same regardless of going straight or down the ramp.

“Rigel” is build on the remote controlled toy called “THM Super Rebounder”. This way I got a platform containing big wheels with gear and motors mounted on a unstable plastic chassis. I have used a wonder stuff called “plastic padding” to make the chassis more stabile. I still use the original 7.2V / 800mAH battery, though it's only lasting around 20 minutes. While rebuilding the toy to a robot, it has only gained a little weight.

The line following sensor

I'm working on an article on how to make the line sensor in a fast and stable way. My line sensor software contains both noise reduction, interpolation for higher resolution and edge enhancement in the software. If I only have low resolution output I can only tell where I am compared to the line, but if I have a high resolution output I can also tell which way I'm moving. To calculate a reliable high resolution result, I have to remove noise and in some way enhance the result that the sensor delivers. The article will not come on display before the competition is over, which is in the beginning at May.

Benny Peter Jørgensen