View unanswered posts | View active topics It is currently Sat Oct 25, 2014 10:36 am






Reply to topic  [ 5 posts ] 
3 tetrix motors in the same PID loop 
Author Message
Rookie

Joined: Wed Jan 23, 2013 6:16 pm
Posts: 7
Post 3 tetrix motors in the same PID loop
Does anyone have any recomendations how to synchronize (3) Tetrix motors, with encoders, in the same PID loop?


Wed Jan 23, 2013 10:45 pm
Profile
Site Admin
Site Admin

Joined: Thu May 24, 2012 12:15 pm
Posts: 596
Post Re: 3 tetrix motors in the same PID loop
Unfortunately, it is not currently possible for ROBOTC to synch TETRIX motors together; for more information on why this is not possible, please see this thread. You could, however, possibly write a custom PID control program that would essentially synchronize the motors.

_________________
Check out our Blog! And our Facebook page!
Need help? Take a look at our Wiki and our Forums.

I just met you,
And this is crazy,
But here's my code now,
So fix it, maybe?
~ Carly Rae Jepsen parody


Thu Jan 24, 2013 12:13 pm
Profile
Guru
User avatar

Joined: Sun Nov 15, 2009 5:46 am
Posts: 1347
Post Re: 3 tetrix motors in the same PID loop
You can write simple PID control yourself to do it. However, if latency is an issue with Tetrix motors, it may not address the issue. But in theory, if you have your own PID control, you probably can tune your PID constants such that the system doesn't oscillate. If the system doesn't oscillate, the latency is less of an issue.


Thu Jan 24, 2013 1:30 pm
Profile
Rookie

Joined: Wed Jan 23, 2013 6:16 pm
Posts: 7
Post Re: 3 tetrix motors in the same PID loop
A basic position loop comes to mind where the position of each motor is compared and the difference between them (error) is used to increase/decrease power to the others. I'm thinking it would be best to declare one of them as a master and other two as slaves. The only exception would be if the correction power exceeds 100%, in which case I would have to slow down the master.

Does this sound like a reasonable approach?

Can you recommend a good resource to provide some PID background?


Thu Jan 24, 2013 1:52 pm
Profile
Guru
User avatar

Joined: Sun Nov 15, 2009 5:46 am
Posts: 1347
Post Re: 3 tetrix motors in the same PID loop
Just google PID control. Wikipedia has a pretty good description of it.


Thu Jan 24, 2013 9:29 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 5 posts ] 

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  



Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by ST Software for PTF.