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I consider using a brushless outrunner motor, designed for helicopters, in my driving roboter. How can I control such a brushless motor with my micro controller? Of course I'll have a separate power source.

The roboter should be able to move forwards and backwards, so I need to control the motor in a way to determine direction of rotation, too. I think this isn't related to the question, but I need to ensure high acceleration.

Specially, I am talking about this motor which is listed in a German shop.

DYMOND MASTER HQ motor

Rocketmagnet
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danijar
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1 Answers1

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You can control brushless motors 2 ways

  1. control with a hall effect sensor http://scholar.lib.vt.edu/theses/available/etd-09152003-171904/unrestricted/T.pdf
  2. sensorless(back emf) control http://www.pmdcorp.com/downloads/app_notes/BrushlessSensorConfig.pdf or you can buy an esc (elcetronic speed control) My advice If you are not knowledgeable about electronic you can buy esc
amra
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  • Thanks. Can I change rotation direction with a sensorless brushless motor? – danijar Aug 29 '13 at 21:21
  • you can change 2 wires.Are you make your sensorless motor driver? – amra Aug 29 '13 at 22:08
  • Generally speaking you can also use other position sensors such as encoders... – Guy Sirton Aug 30 '13 at 00:44
  • @amra The motor is not for steering but for driving. I don't know if that is what you asked. – danijar Aug 30 '13 at 07:46
  • @GuySirton That is good to know. Anyway, do I really need a sensor at all? Can't I just reverse polarity to change direction? – danijar Aug 30 '13 at 07:49
  • @danijar: You can't reverse polarity. The way you drive a brushless motor depends on the position of its shaft. While the motor is in motion that can be sensed by back-emf but when it's not moving or moving very slowly the only "proper" way to control it is with some sort of sensor. (hall effect, encoders etc.) – Guy Sirton Aug 30 '13 at 18:33
  • @GuySirton Okay, but most RC motors for helicopters as well as for cars are sensorless. Thus most controllers are for that type of motor. I guess when the motor stands, it will be powered on two lanes and if the direction was wrong (determined by induction on third line) it changes direction. Is this true and would one notice that in form of not so smooth acceleration? – danijar Aug 30 '13 at 21:14
  • @danijar: Not all those motors are brushless. Helicopters don't care about low speed performance and do care about mass and price so sensorless makes sense. I don't have a lot of experience with sensorless control but I'd expect the low speed performance to be a problem. – Guy Sirton Aug 31 '13 at 01:59