Rover wheels on carpet?


there is a similar thread dealing with static elec. and the rover wheels but that was on the regolith…

So each year my school (mount dora bible) holds an expo at the end of January for potential new students, and each year we bring a robot to show off.

Now, the stage in our gym where we hold the expo has carpet on it, not usually a problem, but with these fancy rover wheels there is the chance for the production of high amounts of static-electricity. Compounded with Florida’s climate, this is even worse, and could lead to possible human or robot injury.

Discussing this with one of our mentors (also my science teacher) I suggested this problem and that led to “I dont know what we could do but we need to do something” and “we wont have time to change the wheels”. And we honestly wont have time to change the wheels, so I’ve been thinking about other solutions to this problem.

#1. Drag a wire? The stage is all wood, so would having a ground wire dragging still work?

#2. Simply cover the wheels with duct-tape? would that eliminate the static?(easy and cheap)

#3. Do nothing?

#4. Find time to change the wheels? (also includes removing and mounting sprockets and tensioning chain)(then prevents us from playing Lunacy in the future)

thats all I’ve come up with so far…

what are you guys’ thoughts on this?

Spray some staticide on the carpet. Worked at regionals at least.

My team ran more than one demo on carpet with zero static issues, but we didn’t have any in the season either.

With the wire idea maybe drag a moist cloth (think washcloth) like a Zamboni from your robot so that it conducts electricity well? I remember them spritzing the carpet at the regionals (there are pictures on CD somewhere).

Is it possible to test on carpet before the demo? This can tell you if you do indeed have a problem. Just be sure to use a length of wire to touch both the robot and ground first, before any humans come in range. (If you hear anything when you do, you know you have an issue.)

As for a wood stage and dragging a wire, unless there is a channel for electricity off of the wood, there will most likely not be a benefit, due to wood being a lousy conductor in general.

Do you have any tread lying around? That isn’t too hard to screw into the wheels with wood screws or other fasteners, especially if you aren’t planning to play in an official competition match again. This is the same as using duct tape, only a little bit more sticky towards carpet. (Trust me, those treads can stick to carpet. They can also leave tread marks, so maybe this isn’t the best idea.) Fabric may also work.

Or, here’s an “easy” one: Bring regolith with you, if you have any, and run on that if you have a decent amount. It’s almost light enough to carry, especially in smaller chunks. (For reference, one of the rolls used in official FRC matches this year was about a 4-5 person carry.)

Interestingly enough when our team practiced on a mostly carpet surface (with some regolith) we didn’t have any static problems either. No problems at regional either. However, at Atlanta we had a weird problem where the cRIO would spontaneously reset itself. Someone suggested it may be static, so we put electrical tape across all of the open ports (serial, Ethernet, and exposed module slots). It worked flawlessly after that.

If you truly have a static problem, then I would suggest taping any exposed conductors that are near the wheels, especially if they are advanced electronic components (e.g. Jaguars, Digital Sidecar, Gyro, cRIO).

In your post it says wood and carpet. Which is the surface that you will be driving on? The team that I was helping out last year drove their robot on a wood surface, it left a lot of marks. I do not recommend it. If your surface is carpet, go out enjoy and see what the robot does, it should be a fun time.

#4. Find time to change the wheels? (also includes removing and mounting sprockets and tensioning chain)(then prevents us from playing Lunacy in the future)

Is there an upcoming Lunacy off-season competition?

the stage has a wooden frame with carpet on top.
And not that I know of, I was just saying…

Eric: the reason I did not mention bringing regolith is we ony have 2 sheets, since we will be letting other people drive the robot it would be nearly pointless(imho) to try and tell a person who has never driven the robot before to try and stay on them. we dont have any tread laying around either.

I’ll test the robot on some carpet on Thursday, and if we have a problem, I’ll probably go with the duct-tape…
we were just assuming there would be a problem.

Shouldn’t take much longer than ~45mins tops, and it’s perfectly reversible.

Though I just suggest protecting all open connections. It’s a bad idea to have things exposed regardless of static risk. Attack everything with a roll of electrical tape; insulate mounting screws and such. It’s impossible for static electricity to effect something it can’t get to.

You might also try fastening a traction material layer over the rover wheels to prevent slippage. Your robot will likely drive differently. Are there any other FIRST teams in the area that you could borrow additional Regolith from to increase your driving surface area?

We had a lo of problems with static, we used a drag wire and it worked perfectly. It will most likely not leave any more marks than the wheels themselves.

Put some fabric softener in a spray bottle and spray it all over the carpet. We do this frequently in our office and at trade shows where enough static would build up from a person walking to cause a laptop to reboot when they touched it.

Way, way back (almost a year ago, now!) we had our initial rolling chassis outfitted for testing with the rover wheels. The programming team was out in the carpeted hallway doing a little driving to make sure everything was working fine… As they drove down and back, you could literally see the static electric discharges traveling between the robot and the wall (where, i assume, they used those hollow metal studs instead of 2x4’s - at least, that’s what they used when they renovated our build space the past few months).

The above results make sense… Think about shuffling your feet over carpet during the winter, then touching a door knob - you get a shock. Do the same thing on a hard wood floor, you don’t (or at least, not as much). Carpet is GREAT for creating static electricity, which is a huge drawback here.

I would suggest changing the wheels - it really doesn’t take too long, and would be a lot safer than any other option.

I’ll do that too.

We had the exact same problem with our cRIO. It worked fine all season long until it started resetting every 30 seconds during matches at Championships. The National Instruments support guys had no clue what was happening, but eventually we figured out that it was a static problem - except our static electricity was generated by our PVC rollers with leathery belts (bad idea). The problem was solved by connecting a wire from the roller bearing block to the frame, which looked rather funny.

As for the rover wheels, I would recommend putting adhesive stair tread on the wheels. It’s like sandpaper, but with a sticky side (meant to be put on stairs to prevent people from slipping). We used it when we did a demo on carpet, and it worked great - no static problems and lots of traction.