Motor ticks per revolution

14 replies [Last post]
saavik
Title: NooBot
Joined: 01/27/2013
Posts:
BotPoints: 26
User offline. Last seen 4 years 16 weeks ago.

The documentation says that the motor turns 1100 ticks per revolution but our experiments show it to be closer to 800. We were wondering if anybody has narrowed it down more specifically.

-Amy coach to Twister Robotics

ruler501
ruler501's picture
Title: NooBot
Joined: 01/29/2012
Posts:
BotPoints: 367
User offline. Last seen 3 years 6 weeks ago.

It depends very strongly on the motor you are using and your robot.
The mean is about 1100. 800 seems remarkably low to me so you might want to try a better testing system
Here is an example of how I'd do it. I'd get extremely accurate measurements of diameter(to within 1mm) and then have it run for ~5000 ticks and measure the distance it has traveled(has to be in the same units as the diameter)
ticks*rot/tick = distance/(pi*diameter)
tick = (pi*diameter*5000)/distance

Jeremy Rand
Jeremy Rand's picture
Title: Botball Youth Advisory Council
Joined: 04/03/2009
Posts:
BotPoints: 1168
User offline. Last seen 3 years 5 weeks ago.

Hi Amy,

If you're trying to figure out how far your robot has traveled, using motor revolutions really isn't a particularly reliable way to do it, because wheels slip. What I generally recommend is telling the robot to drive for a fairly long distance (say 20,000 ticks), measure how far it traveled with a tape measure, and compute the ratio of ticks/mm. Once you've done that, tell it to drive 1 meter using that ratio, and adjust the ratio until you're reliably traveling exactly 1 meter. You can now use the ratio you've found to travel arbitrary distances, and wheel slip is already factored in (assuming that the slip is constant... not exactly accurate, but better than assuming the slip is zero).

-Jeremy Rand
Senior Programmer, Team SNARC (2012-2013), Norman Advanced (2010-2011), Norman HS (2008-2009), Norman North (2005-2007), Whittier MS (2003-2004)
2012-2013 VP of Tech, 2011 President, Botball YAC (2009-2013)
Mentor, Alcott and Whittier MS

peterstrong
peterstrong's picture
Title: NooBot
Joined: 07/05/2016
Posts:
BotPoints: 12
User offline. Last seen 42 weeks 5 days ago.

The mean is about 1100. 800 seems remarkably low to me so you might want to try a better testing system

Ponivnret
Title: NooBot
Joined: 07/29/2016
Posts:
BotPoints: 22
User offline. Last seen 1 year 47 weeks ago.

Thanks for sharing this interesting blog with us.My pleasure to being here on your blog..Iwannacomebeck here for new post from your site
get help with file explorer in windows 10

puisi34
Title: NooBot
Joined: 11/30/2016
Posts:
BotPoints: 6
User offline. Last seen 1 year 29 weeks ago.
Terry
Terry's picture
Title: NooBot
Joined: 06/08/2009
Posts:
BotPoints: 55
User offline. Last seen 1 year 4 weeks ago.

Amy,
The older motors scale tics to ~ 1100/rev; the newest (2016 - Botball lables) have only 800tics/rev. You can quickly validate which motor you have and calibrate it with the motor test screen. If you want your bots to go straight, please match the drive motors, and add a small trim if needed. [do not mix old and new motors.]

History is a race, between Education and Catastrophe

Daizy
Title: NooBot
Joined: 04/12/2017
Posts:
BotPoints: 8
User offline. Last seen 1 year 1 week ago.

I like the blogs you share. In the aussieessaywriter.com.au discount I have seen similar articles. I hope you would keep sharing.

toniantonio
Title: NooBot
Joined: 04/22/2017
Posts:
BotPoints: 28
User offline. Last seen 8 weeks 4 days ago.

I really like your interesting blog. I will surely bookmarked and visit here more often.. Good job, keep it up ...
Obat Stroke Herbal Mujarab Brain Care Capsule
Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters here! It’s always nice when you can not only be informed, but also entertained ...

panistefanin
Title: NooBot
Joined: 05/29/2017
Posts:
BotPoints: 64
User offline. Last seen 1 week 2 days ago.

Hello! this complex question. Here it is necessary to think ...
sprint corporate

Merwan
Title: NooBot
Joined: 07/25/2017
Posts:
BotPoints: 2
User offline. Last seen 47 weeks 4 days ago.

Thanks Peter for this info !
http://www.19216811.win