Field Static Solutions

[Tom Bottiglieri]

Originally Posted by corpralchee

Well if you are Dean Kamen you "spritz" the field with water. At the NH regional the field operators were pouring bottles of water on field near the airlocks and Dean Kamen went around with a bottle of water spraying the airlock.

You mean like this?

http://www.youtube.com/watch?v=o8Mv9LYRNcY

[Al Skierkiewicz]

Midwest was lucky this weekend with a high humidity weather pattern. Static did not look to be an issue. However, a variety of other issues did plague us throughout the weekend.
Draging a ground wire, as pointed out above, can do nothing to drain charge. There is no direct conductive path to ground and the wire or chain does not provide a large enough surface to capacitively couple into the earth below the floor.
My suspicion is that the power connector on the gaming adapter is not made for vibration. A hard hit to the airlock or field border or even robot to robot, could potentially interupt the power connection. It may take some time for the adapter to start sending or reboot on bad collisions.

[David Brinza]

Perhaps something like ACL Staticide should be tested on the regolith. McMaster-Carr sells this in 1-quart spray bottles (7090T37), which should be enough for an entire field.

If it doesn't change the coefficient of friction perceptively, but it eliminates static discharge, it should be applied to all of the fields before practice matches start.

Any teams out there willing to do some experiments?

[Tom Bottiglieri]

Originally Posted by Al Skierkiewicz

My suspicion is that the power connector on the gaming adapter is not made for vibration. A hard hit to the airlock or field border or even robot to robot, could potentially interupt the power connection. It may take some time for the adapter to start sending or reboot on bad collisions.

Perhaps a mandatory dab of hot glue?

We have not had any issues with power connections during hard hits on our practice machine, though.

[Roger]

I'm sure by Tuesday's Team Update time they'll give the explainations and maybe some solutions. I don't know how Dean Kamen is in private but the way things were going in Manchester at the flagship FIRST event I would not blame him for being angry, but angry at what? Giving him the spritz bottle at least gave him something positive to do and walk off the frustration.

I hope someone is reviewing the tapes and seeing how the robots are situated prior to the field zaps. Thinking about it the air locks are the only metal to robot that may electrically connect to the Alliance station wall.

Our robot is a van de Graaf generator with it's vertical corkscrew design. We've grounded the metal frame to the floor but the floor obviously isn't taking it. A parent/mentor/electrician grounded our FRP floor, but only one 4x8 panel, on the small hope that the FRP can carry the charge across. There was limited success on that. Even just sitting in place spinning creates quite a charge.

Everyone knows to ground themselves before touching the driver station, and touch the metal frame before working on the robot itself.

[Jared Russell]

Our robot has never built up any appreciable static, despite doing burnouts on regolith regularly during build season.

One of our patented good ideas this year was installing brushes on the frame that contact each drive wheel at the top of its rotation. Our intent was to keep the rover wheels clear of FRP dust and other debris to preserve maximum traction (and the brushes do that job very well - there is no dust on our wheels even after a half hour of skidding around on regolith).

Question: Could an unintended side effect of these brushes be that static charge is somehow dissipated and/or counteracted? My software-oriented brain defers to someone with a better knowledge of ESD...

[rcflyer620]

I'm not an EE by any stretch, but would dragging a wire from your frame have the ability to turn the robot into a capacitor? And if so, then would metal to metal contact with another robot during a competition create the possibility of interfering with the link to the field?

[Al Skierkiewicz]

Mark,
The robot already is a capacitor and dragging a chain doesn't change that since the field is an insulator. Without knowing for sure, the drag chain and staticide that has been applied to the carpet and the software changes for the FMS have minimized if not eliminated the problem. I am personally going with a static buildup as robots depress the regolith over carpet while driving as the cause of a charge buildup that uses the robot as a discharge path when it crosses the boundary. The staticide fixes that, and the drag chain if it crosses, adds to the solution. Don't fight success.

[rcflyer620]

Originally Posted by Al Skierkiewicz

Mark,
The robot already is a capacitor and dragging a chain doesn't change that since the field is an insulator. Without knowing for sure, the drag chain and staticide that has been applied to the carpet and the software changes for the FMS have minimized if not eliminated the problem. I am personally going with a static buildup as robots depress the regolith over carpet while driving as the cause of a charge buildup that uses the robot as a discharge path when it crosses the boundary. The staticide fixes that, and the drag chain if it crosses, adds to the solution. Don't fight success.

Thanks! Like I said, I'm not an EE however your plain english explanation was a help.

[Tetraman]

Originally Posted by David Brinza

Perhaps something like ACL Staticide should be tested on the regolith. McMaster-Carr sells this in 1-quart spray bottles (7090T37), which should be enough for an entire field.?

Staticide was used on the FLR field, but not on the regolith...I put it on the carpet.

[pitzoid]

The drag chains are doing the most. Most of the issue were bots with high speed conveyor and other type devices for ball control that were basically big Van Der Graph generators. They were very well insulated by the hard plastic wheels being used this year. Certain environmental field conditions make this much worse (like fields on top of ice rinks). The chains provide a ground path to discharge the large voltages that were building on the bots to the regolith and carpet discharging before they have a chance too short at the field boundaries. Not saying its entirely fixed, but things seem much better now....

[Tom Line]

Hey pitzoid - is FIRST now putting drag chains on all the trailers? I haven't seen anything in the update about it, and you're the first person I've heard mention them.

[pitzoid]

Originally Posted by Tom Line

Hey pitzoid - is FIRST now putting drag chains on all the trailers? I haven't seen anything in the update about it, and you're the first person I've heard mention them.

yes

[Al Skierkiewicz]

Tom,
They have been on the trailers for the last two weeks as well as the staticide application to the carpet borders. They don't interfere with the game or the trailer movement and the trailer tongue is conductive to your robot unless you have chosen to insulate the hitch in some fashion. Your inspectors will be able to tell. There was no need to include this in a TU so nothing was contained in the last one.

[kjohnson]

Originally Posted by Al Skierkiewicz

They have been on the trailers for the last two weeks as well as the staticide application to the carpet borders. They don't interfere with the game or the trailer movement and the trailer tongue is conductive to your robot unless you have chosen to insulate the hitch in some fashion.

We had the drag chains on the trailers at the NASA/VCU regional, but did not use the static guard on the carpet at any point during the competition. I never heard any of the teams complain about static issues, and this was the first year I NEVER got shocked by someone's robot.