Howdy
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?
Any thoughts?
thanks dpa