4 Wheels 4 More Fun

Lego Unicycle Robot
Now meet another balancing robot. This one balances on one wheel and apparently uses two RCX bricks and four sensors along with three tires to maintain balance on the axis perpendicular to its unicycle. The robot balances on the main axis by directly powering the wheel. The axis perpendicular to its unicycle is balanced by the set of rotating tires.

It uses 3 pid controllers
pid = Kd * errdiff + Kp * err + Ki * Errint
Kd, Kp, Ki are tuned via remote control code.

sources on:
http://woerden-dynamics.jouwweb.nl/gallerij-links/gallerij

see also: http://en.wikipedia.org/wiki/PID_controller

Check out the video!
More info on:
http://news.lugnet.com/robotics/?n=22181
and
http://www-clmc.usc.edu/Resources/Software

Category:

Howto & Style

Tags:

• LEGO
• Unicycle
• balancing
• single-wheel
• robot
• one-wheeled
• self-balancing
• Idling
• inverted
• pendulum
• PID
• control
• brickos
• legos

[fedekaare]

I've got a budy. him and i have been playing with the idea of a RC AH-64 Apache. This would be flyed FPV with remote camera and headtracking goggles. this model would be made with fly by wire and this is where we lack the expertise that you have. would it be possible to make you balancing software transferable to flying a helicopter or/and a plane?

Hope you still read this... : )

[Vegakade]

This robot uses light sensors and pid controlers. The light sensors won't be much use for you. Maybe the PID controlers will. Better sensors for a helicopter will be gyro and accelerometers (look also for my other robot NXT-body balance). But you better search for IMU and Helicopter on a search engine.

Good luck

[jvpommeren]

Absolutely a great robot!

How did you tune the PID controller parameters? Trial and error or some advanced technique?

Did you measure what the maximum recoverable angles of your model are? In both (tilt and roll) directions?

[Vegakade]

Thx, I started with manualy tuning(Lego Remote Control) while a supervised learner on the PC watched the process(through the IR-tower). The Learner(LWPR) could do the tuning quite well. No angles were calculated, only light sensor values.

[Vegakade]

look on google for:

Locally Weighted Statistical Learning Software download

[rocketman468]

just so awsome :D

[nattavision]

this is great but it seems to be wobbling alot, looks like it would fall over as soon as u touch it!

[Appelsappel]

awesome

[RoboTekno]

i love it, especially since it is made form legos

[Limpfittz]

Amazing