|Posted by Klein on July 19, 2012 at 12:40 AM||comments (1)|
Apologies for neglecting to post a follow-up to the 2011 contest results, but I've been hiding in shame. I put Octowobble on the line following course and so got a minimum score for showing up. The behavior was so erratic that I didn't try any more contests - I just posted an "Out of Order" sign on the bot and tried to enjoy the day.
Scores and pictures are available on the botlanta site.
|Posted by Klein on October 18, 2011 at 11:40 AM||comments (0)|
Registered for the 2011 Robot Rally today! Start the countdown clock ... 24 days.
Robot Rally Registration
Date of Submission: Tue, 18 Oct 2011 09:37:23 -0600
Name : Tim Klein
URL : http://kleinbot.webs.com
Site Name : KleinBot
Robot's Name : Octowobble
Polyathlon: Simple Line Follower,Advanced Line Follower,Beacon Killer,Beacon Killer with Obstacles,Dead Reckoning,Bulldozer
Processor Type : AVR(Arduino)
Navigation: IR Bumpers,Beacon,Other
Other Nav Systems: Pololu reflectance line sensor, wheel encoders
Robot Info: Octowobble finished in second place at last year's Rally. Tim and Ben (father and son) have been working on the improvement list, and hope to have a more consistent performance this year. The robot is named "Octowobble" because it's octagonal body shape. The 'wobble' was added because it sounds good. Much of the robot is made from salvaged materials -- Roomba wheels and edge sensors, a surplus aluminum sign, erector set, and a couple of plastic Easter eggs.
|Posted by Klein on October 17, 2011 at 11:20 PM||comments (0)|
Well, we didn't get much done before the school year started in early August, so progress ground to a halt while Ben worked on (non-robotic) school work. However, this past weekend was between academic quarters and part of Fall Break, so Ben got lots of time with Minecraft and I got him to help a little with Octowobble.
The result - we worked out a motor driver bug and finished up the edge sensors.
Driver bug - The motor drivers (LMD18200) weren't consistently driving the motors. They would whine and the wheels would only turn if pushed. Once started they ran well with good speed and power. I reviewed the data sheet and noticed that the example schematics used large caps on the supply lines. A small note in the docs suggested 100 uF per amp of running current. Adding a 330 uF did the trick (overkill, but that's what I had on hand).
Reluctant to disassemble the drivers that I had already built, and inspired by Dale's implementation (Polymax Improvements 2009), I used the extra LMD18200s that I ordered last year and built new freeform driver assemblies, attached directly to the body. Putting the drivers next to the motors reduces line loss, and the large body mass makes for a great heat sink. (I'll post pictures of this soon. It'll make more sense then.)
Finally, we copied the single working edge sensor and glued those in under the shell. I've yet to use them in working code *on* the robot, but off-robot testing and voltmeter readings suggest they will work ok.
|Posted by Klein on July 23, 2011 at 11:47 PM||comments (0)|
We've been spending a few hours here and there in July without much progress. Some things are getting done, however. Circuits for the motor encoder and edge sensors are coming along. Software is mostly working. The two have to evolve together.
I've posted more pictures in the 2011 Robot Rally album.
|Posted by Klein on July 6, 2011 at 9:21 PM||comments (0)|
We're back! Octowobble is getting ready for the 2011 Atlanta Robot Rally. Stay tuned on this channel for further updates.