To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.robotics.nxtOpen lugnet.robotics.nxt in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 Robotics / NXT / 78
77  |  79
Subject: 
Re: NXT Motor Encoder Accuracy and Dead Reckoning
Newsgroups: 
lugnet.robotics.nxt
Date: 
Sun, 13 Aug 2006 14:10:59 GMT
Viewed: 
11359 times
  
Dick, the article you referenced with the PID controller is excellent.

I spent a lot of time trying to do a straight line with an RCX model a few years
ago, but with a different approach:

It was track-driven and the drive shaft extension on each side engaged the two
ends of a differential.  The motors drove in opposite directions (driving the
model forward) and in a perfect world the 'casing' of the differential should
have had zero rotation.  But the motors drive at slightly different speeds, so
you do, in fact, have VERY SLOW casing rotation and you can sense that and
correct in any number of ways.  The nice thing is that when you 'correct' the
casing to the 'center position', however far the model travelled, both tracks
will have travelled exactly the same distance.

I'm sure you could use this technique to check both the accuracy of the NXT
motors and software blocks.

Here is a link to the 'LEGO LUGGER' showing details of the differential setup.

http://legoprojects.jdkalpin.com/Lugger1.htm

Jerry



Message is in Reply To:
  NXT Motor Encoder Accuracy and Dead Reckoning
 
Has anyone done any experiments on the accuracy of the NXT motor "move to" block? If so, can they post their results or impressions? I know NXT supports PID calculations to synchronize two motors and run in a straight line. Can you use this to drive (...) (18 years ago, 13-Aug-06, to lugnet.robotics.nxt)

4 Messages in This Thread:



Entire Thread on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact
    

Custom Search

©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR