Static Buildup

For maneuverability purposes, the back two wheels on our robot are made from the same material that we were required to use last year for the wheels. Unfortunately, this gives us the same problem with static build up running on carpet. Last year we were able to use a linolium tiled room for practice, but this year we must use carpet as that will be the competition surface.

We’re pretty sure that static buildup has fried one of our jaguars, and we’re worried about the rest and especially our cRIO. Does anyone have any suggestions for eliminating the charge?

Our ideas so far:
dragging some chain or rope to transfer it to the ground (just for testing, not for competition)

hooking up a wire from the frame to the ground terminal on the battery (is this legal?)

It is illegal to ground your frame. (In fact, this is a big problem since the casing on the cRIO and camera are both grounded. You should use a multi meter to make sure this isn’t happening.)

Last year there were a lot of team that had this problem. My team even saw static sparking it was so bad!!! I would recommend looking at threads from last year. One of the ideas that came up was having a wire running from the frame to the ground this should keep the robot from having a static charge.

Hope that helps!

EDIT: Phoenix beat me to it, but heres the rule quote;

<R43> All wiring and electrical devices, including all control system components, shall be electrically isolated from the ROBOT frame. The ROBOT frame must not be used to carry electrical current (e.g. this is necessary due to polarity reversals that occur under certain operating conditions such as during motor direction reversals).

R43 would make your last idea a no go.

As for the other stuff, Im not really sure. Probably best to ask in the Q&A.

Rafael,
The source of the static is the interaction between the wheel and the carpet. The accumulated charge is then transferred to the metallic parts of your robot through several different paths. Most notably from the wheels to adjacent parts and to a lesser degree from the robot moving across the field. In past years, teams have been allowed to attach a drag wire to the robot frame as long as it did not produce an entanglement hazard for other teams. This was thought to help drain the accumulated charge or at least to place the robot and the carpet at a lower potential difference. There is nothing this year that allows this practice so ask the Q&A. Since the battery does not present a path to drain the charge, connecting the frame to the battery does nothing for static. This connection does produce a condition where contact with another robot’s electrical system can cause voltages to occur that exceed the rating of some electrical components and therefore can cause significant damage.

Al,

In my opinion, there is no rule which prohibits this.

Regards,

Mike

We had this same issue and we solved it with a two inch length of chain attached to our frame. It did the trick and it has no way of going outside our perimeter and always stays in contact with the ground.

Mike,
There are a variety of reasons that the GDC might rule against this. I for one do not second guess their decisions.