This is hard to figure out without seeing it, but couple of questions come to mind:
1. Has your team tried to reduce the power, to say, 50 or below?
2. How is the robot balance and center of gravity? For example, does it happen if the attachments are removed?
3. I noticed that sometimes loose wheels can cause strangest behaviors in movement, so not a bad idea to check if the any part of the attachments/ frame and wheels are not loose.

Just a comment: The great fun of FLL is ruined especially to rookie teams because of all the variability in the NXT Robots. These are no doubt complex products, and it is not easy to get consistent behavior. It requires some experience and lots of practice. This is not my first year, but I am still learning.

I wish Lego or FLL would make it easier for all the teams - and improve the fun factor - by providing some basic information/ instructions/ best practices to reduce variability as part of the NXT kit or FLL kit. Just a thought. I'd like to see more teams having more fun than struggle so much.

Nagesh


On Thu, Nov 4, 2010 at 10:15 AM, Mandy Wilson <[log in to unmask]> wrote:

This turn does not involve sensors.  It’s just a plain point turn. 

 

From: First Lego League in Virginia and DC [mailto:[log in to unmask]] On Behalf Of Eric Palmer
Sent: Thursday, November 04, 2010 10:09 AM
To: [log in to unmask]
Subject: Re: [VADCFLL-L] NXT merry go round effect

 

I wish I knew what causes this. We see it occasionally. Something lose wires. Sometimes changes in battery levels. Do check to make sure that if you are using sensors that they are working reliably.


On Thu, Nov 4, 2010 at 10:06 AM, Mandy Wilson <[log in to unmask]> wrote:

 

 

Our team has a part of its program where the robot is supposed to turn some nominal amount (around 30 degrees) and for some reason every 5th run or so, it spins about 120  degrees.  They have put a reset motor block, a break block and even a 1 sec wait block in front of the errant turn in order to stop the issue, but nothing they have done works.  They’ve even tried deleting the block and putting another one in.  They thought it was the gearing on the wheels coming loose which also causes it to act up, but on the 6-9th run it works fine and then at run 10 it does it again.  Well not quite that predictable, but you get my point.  Has anyone else had this problem and is there a way to fix it, or should the team just be resigned to blow a round at the tournament?  Thanks for all the help – this is our first year!

 

Mandy

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--
Nagesh Chintada
Phone: 703-829-0284

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