Originally Posted by Andrew Schreiber (Post 1198654)

I'm not sure whether the 3WD platform is touchier. My gut feeling tells me that it would spin a little easier and would show this problem a little more but I do not have data to back this up. I'm open for suggestions on how to collect this data.

I would disagree that simply placing it in brake mode would fix the core problem of motors moving at different speeds. It may fix the majority of it but for our team it was worth the $150 it cost to actually address the issue and to give us accurate autonomous navigation. It was also worth it to teach the lesson of the importance of feedback systems to my students.

I guess, my suggestion to OP would be to try the cheap and fast solution and if it meets your needs cool if not move on to using feedback.

Originally Posted by Nemo (Post 1198662)

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.



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.