Has anything happened to the iPad in the days leading up to this issue; for example, a drop, a repair attempt or contact with water?
The only other thing to try is to restore the iPad but if you don’t have a current backup, you may be reluctant to do this. Otherwise, you need to open up the iPad (check out this [guide|36023|guide]) and try another battery to see if that will solve the problem or not. Beyond that, you really need to have it looked at as the problem may be at the logic board level.