It was speculated that static build up and discharge from machines to the corner player stations (Airlocks?) could have cuased some field system issues at regional events this weekend.
The purpose of this thread is for people to discuss suggestions to prevent this in the future. lets share some of our ideas here.
I suggest that FIRST modify the trailer design to include a ground wire that drags on the floor under the trailer. The wire could be fixed to the trailer tounge where it extends into the trailer body. The wire would be under the trailer and not visible.
This would also create a uniform solution rather than asking teams to take chassis grounding into their own hands.
There was an information sheet released awhile ago detailing how you should do this. it involved attaching a pwm cable to the bottom row of pins on the IO ports and attaching the other stripped ends to the closest screw.
as for the robot, we just bolted a piece of wire to the bottom of our robot. very easy fix, only took a few minutes.
I don’t think the driver’s station grounding wire is enough. It grounds the circuit to the case, but the case isn’t grounded to anything. I think there should be a ground strap that clips onto the driver’s station that’s connected to an earth ground. Similair to an anti-static mat used when working on electronics.
Brian
I didn’t have, nor hear about, any static problems at DC. Has anyone actually had problems with buildup, or are we discussing how to prepare against the pickle rebellion?
My team (964) bricked our station at the Buckeye regional, and there were a ton of other teams having issues with their system. The fix with the grounding to the casing worked, though.
Somewhat related, the Buckeye field controller used a cheap USB soundcard for the game sounds, and it was shorting out our system all-day Thursday. So lot’s of static/ESD issues here.
Well if you are Dean Kamen your “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.
For a drag chain or grounding strap to discharge a static charge on a robot it would need to contact a conductive surface. Regolith is nonconductive. Please tell me how this will help.
We had both alliance control stations die because someone would ram the stations and the grounding wire preventing the damage of the controls came loose. We went down for like an hour twice because of this. Also on thursday we had an average down time of 10 min. they fixed it for friday and it worked really nicely. Some of our mentors have mentioned that they do have grounders for people to keep you from killing your electronics after your robot builds us so much static electricity. We also had a lot of teams loose the control boxes for no reason. The NI guy who did a TON of work for the design and programing of the control system was really frustrated. Luck-fully for week 2 competitors most glitches have been worked out for you.
Kansas City had static problems, along with grounding issues on the main driver station junction box. The FTA stated that after several high speed collisions with the drivers station by robots the junction box grounding was comprimised.
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.
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?
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.
