View Single Post
  #29   Spotlight this post!  
Unread 06-05-2009, 20:38
gburlison gburlison is offline
Mentor
FRC #0662 (Rocky Mountain Robotics)
Team Role: Mentor
 
Join Date: Sep 2002
Rookie Year: 2000
Location: Colorado Springs, CO
Posts: 245
gburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to allgburlison is a name known to all
Re: Sensorless back_emf speed controller

Quote:
Originally Posted by Al Skierkiewicz View Post
Chris,
I also remember a distinctive ripple that was associated with the switching of the brush assembly. Don't quote me but I think the ripple voltage was in the 0.2-0.5 range.
Al,

Do you think that this ripple could be sampled? I assume that the frequency would be proportional to the speed of the motor. Perhaps a Schmidt trigger could clean it up. This could then be sampled by the cRio to determine the speed of the motor. Not quite the same as back emf speed controller, but would not require a mechanical sensor to determine speed.
__________________
Gordon Burlison - Mentor
662/Rocky Mountain Robotics
"Every silver lining's got a Touch of grey - Robert Hunter"
"No sense in being pessimistic, it wouldn't work anyway"