Quote:
Originally Posted by Tom Bottiglieri
The FRP is non conducting, so there is no path from the robot to the ground while it is driving around. If you are driving full speed into a wall or airlock, there may not be enough contact with the carpet to discharge the build up into the ground before it contacts the field frame.
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Yes the FRP is non-conducting but the use of a few static discharge wicks in light contact with the FRP floor may equalize the potential between the floor and the robot. This is common practice in aircraft design where static discharge wicks attached to control surfaces and trailing edges help prevent buildup by discharging to the air. It is also good practice to bond any metal parts that may be floating from the main chassis, except of course for the camera and cRIO.
In Florida, we usually have such high humidity that static is rarely a problem. But this year, with the unusual cold, many days here remind me more of the static environment of the Northeast or Canada. Our students have been getting zapped left and right, much to their surprise. We haven't had any resulting electrical problems (yet).
Depending on the exact mechanism involved in the static related resets, it could be that a static drain resistor of 100K - 1Meg between chassis ground and electrical ground might afford some protection. This would at least prevent very high static voltages from building up between the chassis ground and the electrical system without interfering with the safety aspects of the electrical isolation. In fact, it would be pretty easy to have a jumper with a resistor that could be installed (or not) to see if it makes a difference. Testing in a low humidity environment is certainly needed and perhaps this could be done in practice matches next week.
We had ESD problem a few decades ago with a communication device that output to line printers. The issue only cropped up in a few locations in the winter and IIRC we solved it with a drain wire on the paper basket and a couple of discharge wicks in the paper path. Although the technology was older (Z80's), the problems were similar - mysterious unexplained resets.
I think FIRST need a "Tiger Team" on this to get control of the issue by next week. Just my $0.02