RT @BotJunkie: Rod Brooks is gonna kick things off here in a sec- we're big fans over at @IEEESpectrum of course spectrum.ieee.org/automaton/robo… #xconBot
Balancing Robots get Smaller
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| Mini-Bender | Mini-ISIS |
The first rework of the PCB is done. We wanted to make another balancing robot, using off-the-shelf motors that wouldn’t set us back lots of $$$. As you might remember, Bender and ISIS are using surplus motors, which we can’t hope to find again, unless we get really lucky. We found some smaller motors that were only $15 new, and that had tail shafts to allow the mounting of a small optical encoder for motor feedback. So, we had to scale down the mechanical design to one that the motors could accommodate.
Although we built two of these, they are both not yet perfect. Bobs was the first to be up and running. It still needs a little bit of software work to make it more stable, but initial tests are encouraging. Once I had it balancing, Bob took it home, and mounted a much larger battery pack on it than I had used in the initial tests. When he showed up with it at the latest robot club meeting, I was really surprised to see how the extra mass helped the balancing stability. Lately we have also been experimenting with gyro mounting locations, and it appears to be much more stable with the gyro/accelerometer board mounted down low on the robot, rather than up high, which is something that was not an obvious thing to do.
Here are some video clips of mini-Bender. These clips are in Windows Media Player 9.0 format:
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Mini-Bender #1 - Here he is, balancing on the kitchen floor, looking pretty stable. |
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Mini-Bender #2 - I have the radio control unit hooked up, and am taking him for a spin around the kitchen floor. It’s a bit difficult to drive and film at the same time, but at least I don’t run into anything  |