What you're asking for does not exist. USB and 1394 are two completely different protocols, a USB to 1394 adapter / cable does not exist, You will need to find a computer with 1394 on it, this is more easily done with a Mac Book using Thunderbolt to 1394 adapter or with a desktop PC with a 1394 card in it. Then connect that system to your console with a router so you can then control it via iPad.
This article is a bit dated from 2013 discussed on what to know when looking for PC laptops with 1394.
