Self Balancing Robot With Wii Parts

[Moser] is looking to build a quadrocopter sometime in the future, without plunking down a good chunk of change for a kit model. Looking for a good place to start he figured why not work on the control system. Thinking that the balance of the flying platform of doom would be similar to working out a self balancing robot he spent a couple days and made his self balancing robot.

Armed with a plan, and a logic analyzer, he went out and got a  Wii Motion Plus, which is an inexpensive three axis gyroscope, and a nunchuck which features an accelerometer which both can be found in just about any strip mall. After fiddling for a day getting the Wii nunchuck and motion plus to play nice all it took was a little more time to code up the self balancing routines.

And while its not perfect, all its going to take is a little tweaking and maybe some faster servo motors to get things up to top notch.

Join us after the break for a couple quick videos.



8 thoughts on “Self Balancing Robot With Wii Parts

  1. The main thing that is causing this jitters in this is likely the backlash in the servo gearbox.

    When you’re controlling an inverted pendulum, you linearise it around an operating point. Due to the maximum angular rate of the servos, you are typically left with a very small range within which the system can be controlled. With the backlash in the gearbox, you introduce a hysteresis nonlinearity, so each time you change direction you lose a few degrees, and often this loss is close to the total angle in which the system can be controlled.

    This nails beginners all the time because servos are a good choice for hobby electronics since they can be easily modified to be used as motors for wheels in applications where precision isn’t critical, but is very critical when one is trying to control an unstable system.

    The solution is to use motors with direct drive (ie. without a gearbox), though this usually requires a separate power source (due to noise) and power electronics.

    Cool little project, good luck with the quadrocopter.

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