[MCahoon]

Would the static charge accumulation on the chassis be discharged through a drag wire when the surface it is dragging against is the an insulating material?

The same problem exists with helicopters - in a past life, during training to help with rescue of mountain climbers - we are told DO NOT touch the helicopter until it touches the earth/snow or someone discharges it - it can seriously injure a person (kind of a mini-lightning strike). The rotors spinning through the air generate large amounts of static charge and with their large frames can store huge amounts of charge.

The wheels (insulator) spinning/rubbing against the plastic floor (insulator) generate the static charge. The contact point of the wire/chain on the floor will charge quickly to the same static voltage as the robot frame. Given some time and moisture in the air, etc, it will bleed off the surface. You can't "rub" it back off into the floor - and you can't force charge to flow into the insulator. Seems like if anything you have just added another rubbing contact to generate even more static?

Seems like we should be giving the team members who go onto the field to retrieve the robots a "wand" which is connected through something about 1 Mohm to a grounded plate somewhere which IS connected to earth (essentially a lightning rod) to touch the robot "touch here" spot. Should FIRST be looking into a conductive coating for the floor such as is used on factory floors to prevent static buildup?

My 2 cents