It appears that the iPad believes that a charger is being connected/disconnected. This could be caused by a damaged charging port or a logic board issue. I would start by inspecting the charge port on the bottom of you device. If you can, shine a light inside it and check to see if there is any debris or if the copper pins inside it are damaged or bent. Magnification will help!
If the charging port looks good, then the problem could be on the logic board.
Unfortunately, unless there is debris inside the charge port, the other options are not really DIY repairable. You will need to find a repair shop or deal directly with Apple.