Swap the motors, see if the direction of turn reverses?
From: First Lego League in Virginia and DC
[mailto:[log in to unmask]] On Behalf Of Bob and Ann Henshaw
Sent: Tuesday, October 23, 2012 7:16 PM
To: [log in to unmask]
Subject: [VADCFLL-L] looking for help with erratic robot behavior
I am a 5 year veteran home based coach with a 2nd year team of 10 year olds.
We are working with a Mindstorms NXT system that we purchased new last year,
with a fully recharged battery. We are experiencing several intermittent
erratic behaviors (listed below) that is driving our team crazy. Please let
us know if you have any debugging suggestions.
1. After completing a planned series of instructions, with the last
instruction having 2 wheels turning equally (straight line), the robot
suddenly makes an additional turn (one motor, rotating robot about 30 -
40degrees). This occurs even after deleting the program, recompiling and
redownloading it, and even after adding an all motor stop block to the
program. Our team is referring to this as a ghost and are convinced that the
robot is now haunted, just to get us in the Halloween mood.
2. The robot, using a two wheeled turn (one motor going forward, one
going backward) intermittently turns too far or too short. Programming is
being done in rotations for both motors. Because both motors are running
together, I can't tell if it is related to the problem above. This occurs
about 1 in 5 runs.
I do not think that this is a cable issue, as we are not seeing anything
beyond the usual minor navigation errors due to lineup, wrinkles in the mat,
etc. That leaves the motors and the NXT itself. Could this be a bad servo
motor and if so, is there any way to test them?
Appreciate your suggestions!
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