One of the best strategies would be to avoid tipping over in the first place. Build a robot that can go over the bump without tipping, and make sure the drivers know how to do it without tipping, every time.
As a rookie team, I think you will find that driver practice is the most important thing you can give the team. So, forget a self-righting mechanism (or, build a
Weeble) and put your energy into more important things.
My 2 cents.