Electric Unicycle Project - Brushless Motor Controller?

Discussion in 'The Projects Forum' started by joe426, Dec 4, 2011.

  1. joe426

    Thread Starter Active Member

    Aug 11, 2009
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    I'm building a self balancing unicycle which uses this brushless hub motor (click hub motor on the left column). For balancing purposes, I need to be able to rapidly move the wheel forwards and backwards.

    I've researched a wide variety of controllers, but after posting on an electric vehicle forum, I learned most commercial controllers have safeties in them which prevent forward and backward movement.

    I still have yet to find one capable of the fine motor control described above. Any leads/advice would be greatly appreciated. I'd prefer one with regenerative braking, but at this point I'll take anything.

    Thanks!
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    The first motor you linked has built-in controller. You will most likely have to build one by yourself, so you should find a bare motor wihtout it.
     
  3. strantor

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    Oct 3, 2010
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    have you looked at brushless servo drives like whats used in cnc machines?
     
  4. joe426

    Thread Starter Active Member

    Aug 11, 2009
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    I actually ordered a version without the built in controller because the built in controller is 1) notorious for overheating and 2) made for electric bikes (constant forward motion, not quick forward-to-backward control)

    No, do they make ones large enough to handle 44v @ 25A?
     
  5. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    I suppose it is a three-phase brushless motor, right? It shouldn't be hard to source a driver to it for this voltage and current. To make the unicycle work you will have to build your own controller anyway, but the driver will take care of the power electronics.
     
  6. strantor

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    Oct 3, 2010
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    Before I go much further, when you are talking about a hub motor (I know what an ebike hubmotor is) I'm thinking the motor is parallel with the ground; spinning in free air; The "self balancing" gyroscopic thing. Not a traction motor that pushes against the ground. Am I correct?
     
  7. joe426

    Thread Starter Active Member

    Aug 11, 2009
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    Yes, it's a 3 phase brushless motor. Do you have any recommendations on a driver?

    No, it pushes against the ground. I'm building a DIY version of the SoloWheel.
     
  8. kubeek

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    Sep 20, 2005
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    Does the motor have any sensors? It should have at least one.
     
  9. joe426

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    Aug 11, 2009
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    Yes, it has hall effect sensors. I believe it has 3.
     
  10. shortbus

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    Sep 30, 2009
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  11. joe426

    Thread Starter Active Member

    Aug 11, 2009
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    Thanks for the links. Those OnSemi chips seem to be the ones everyone is using. Basically, what I'm hearing from everyone so far is that I need to build my own motor driver and brain. Looks like there is no way around it :/
     
  12. michel pet

    New Member

    Jan 24, 2013
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  13. Mandrake90

    New Member

    Nov 23, 2016
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    Thank you guys for all these tips. I'm trying to design and build my own self balancing unicycle and I need to find a good brushless hub motor. This topic helped me a lot ;).
     
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