View Single Post
  #13   Spotlight this post!  
Unread 04-12-2012, 16:22
Nemo's Avatar
Nemo Nemo is offline
Team 967 Mentor
AKA: Dan Niemitalo
FRC #0967 (Iron Lions)
Team Role: Coach
 
Join Date: Nov 2009
Rookie Year: 2009
Location: Iowa
Posts: 804
Nemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond reputeNemo has a reputation beyond repute
Re: Omni-wheel accuracy

Quote:
Originally Posted by Andrew Schreiber View Post
I would disagree that simply placing it in brake mode would fix the core problem of motors moving at different speeds.
I completely agree that using encoders is better overall and that it's a great thing for the students to learn how to do that.

In this specific situation, I don't think the core problem is best described as "motors are moving at different speeds." According to the quote below, sometimes the motors are continuing to run after the driver stops telling the robot to drive, while other times the motors stop right away. That problem as described would go away if the motor was told to stop instead of letting it coast.

Quote:
Originally Posted by mrcheese123 View Post
When the bot goes diagonally, the motors slow to a stop at random (not every time) rather than just stopping. Also, occasionally, when the train is rotated, two motors stop and two motors roll to make it roll about an extra 45 degrees.
We've had this exact problem with the same style of omni drive, and it drove a whole lot better after we incorporated the "stop motor" command when we weren't commanding the robot to drive.

No philosophical disagreements here... like I said, I agree that using encoders is better.