I've been chasing noise related to some new Polaroid sonar
modules on a 6-wheel robot, and it appears that I can
reduce it substantially by placing a grounded shield
between the motors and the sonar controller boards.
I had not noticed any noise problems before, but it
seems that the high gain analog amplifiers in the sonar
controllers are particularly sensitive.
By powering the sonars from a separate bench supply,
I was able to narrow the noise problems in the sonar
to the 24 DC motors that are mounted nearby. Placing
a sheet of aluminum between the sonars and the motors
had no effect, until I ran a clip lead to the aluminium
sheet and grounded it to the robot power supply. At that
point, the noise disappeared almost completely. RF?
I had previously added the recommended trio of noise-
suppressing .1 uf caps on the motor termimals and
between the terminals and motor case for each motor,
but I noticed that the motor case itself is not
grounded. When I added a ground wire to the motor
case as a test, it seemed to make the noise problems
_worse_ rather than better, and I removed it.
So my question to the experts in this group is, do you
routinely ground the motor cases of your robot motors?
17 years ago