Tuesday, July 13, 2010

Day 6- Our Kryptonite

The main focus of was creating the one thing we've never been able to successfully construct: a line following robot. The horror! Both with the Mindstorms kit and the Tetrix kit, our bots have been able to vaguely move in the general direction of the line, but never along the line exactly, as other bots have been able to successfully accomplish.

Earlier this morning, we completed our battle bots with the Tetrix kit, and pitted them against each other in the square box, which ended in a three-way tie. Here are pictures of the bots and videos of the first two battles:
















Battle 1:
video

Battle 2:
video

Afterwards, we moved on to adapting our bots to follow a line of black duct tape, as we had done with the Mindstorms kit on day 2. We attached a light sensor to the front of our bot, and opened our old line-following program that used proportional controls. However, while testing our bot, we ran into multiple problems, both with the program and the mechanics.

First, with the program. The equations of the proportional controls were rearranged such that equal power was being added and subtracted, and the constant was multiplying the entire equation rather than just the portion that created variation. We also changed the style of motor to match the Tetrix kit, and added a watchdog to ensure the program ran smoothly.

In terms of mechanics, we noticed that at very low power levels, our bot would still rush forward at top speeds. This was later accounted to us using direct drive between the motors and wheels, rather than using gears in between. At the end of the day, we were in the process of incorporating gears into our bot in order to slow it down significantly.

Although we haven't had much success in the past, we hope that the combination of altered program and mechanics will finally help our bot follow the line, and conquer our kryptonite!

1 comment:

Bill said...

Great comments, Lara. You will conquer your kyrptonite! Your reflections along the way will help us create resources for future students who face their own kryptonite!

Keep up the good work and as you complete this task, start thinking about what Tetrix can be used for that LEGO can not. This will make using Tetrix (with all of its sharp bits and pieces) worthwhile. I know from my experience with my students that once they were inventing and creating large robots to solve challenges that were not easily solvable with LEGO then they really enjoyed the process much more.

So -- is a frisbee chucking bot still being considered?

Bill Church