Akash,
I'm not really sure what you mean by "exceptions". No part of an FLL robot should be an item that appears on the
TSA Prohibited Items list.
The only prohibition regarding batteries is that you must not travel with loose Lithium batteries in checked baggage.
I would agree with the suggestion to contact your airline (or TSA as the post above me suggests) if no one posts here that has done this with an FLL, FTC or Vex robot. My guess is that you just send it through the X-Ray scanner in a separate tray just like a laptop.