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Topic: Balancing robot for dummies (Read 145 times) previous topic - next topic

BrianBot

I've decided to tackle an Arduino balancing robot for my final design project for my two year college program. I may make my own thread documenting my progress (similar to yours), but maybe not (your walk through is impressive).


Brian!

BrianBot

I was thinking about using:

sensors: http://www.robotshop.ca/sfe-ardupilot-sensor-board-six-degrees-of-freedom-imu-main-1.html

motors & wheels: http://www.robotshop.ca/tamiya-72101-gearmotor-foam-tire-set-1.html

motor controller shield: http://www.robotshop.ca/adafruit-motor-shield-kit-arduino-4.html

Arduino controller: http://www.robotshop.ca/arduino-uno-microcontroller.html

I will settle on a battery pack and voltage regulator once I final my component choices.

The MCU is 32-bit with a 16MHz crystal, the motors' RPM is 242  and the wheels are 2.5" diameter. Are these fast, large, and good enough to balance properly? My instructor seems to think there will be problems with different torques of each motor. How much validity is in that? Any other issues I'm overlooking before I start?

It does feel like I'm not entirely sure what I'm getting myself into, but I have a few months to figure it all out. This forum will make my life much easier; I salute you  [smiley=beer.gif]


Brian!

kas

#207
Jan 11, 2011, 11:01 am Last Edit: Jan 11, 2011, 11:11 am by kas Reason: 1
Hi BrianBot,
Welcome and good luck for your project  :)

Looking at your shopping list, I have the following comments:
motor controller shield:
This device will definitly not cope with the amperes needed to feed your motors  :-?
Look here (initial post)

motors & wheels:
The wheels are wide and soft, which is good for balancing
Wheel diameter could be higher
You need encoders (at least one). How will you afix them ??

Quote
My instructor seems to think there will be problems with different torques of each motor.
How much validity is in that?
This is addressed with the second encoder

Feel free to document you project here
This thread is now very visible from Google, this is convenient for discussion with non Arduino jerks

BrianBot

I was denied permission to use shields, anyway, as it was declared "too easy". I suppose that's convenient.

I got my hands on a free L298N H-Bridge: http://www.st.com/stonline/books/pdf/docs/1773.pdf
Unfortunately it only can handle spikes of 3 A (repetitive 2.5 A). Did you ever get an idea of what currents are used? I plan on making the bot relatively small...

Also, have you ever run into speed problems from the microcontroller? Is 16 MHz fast enough?

My understanding was that the sensors act as the feedback to tell the motors direction and speed, so a motor encoder is not necessary. I see you made the same statement in your initial post.

Big Oil

Check out the "murata girl" a unicycle robot that balances forward/back and left/right.  It is at the 1:35 mark on the youtube video.
http://spectrum.ieee.org/tech-talk/consumer-electronics/portable-devices/ces-murata-boy-and-girl-strike-again

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