The Automaton will attack either with a physical strike or Rocket Punch, an attack that deals damage to the entire party. After a few turns, they will use Limiter Rescission, an ability which increases their P.Atk by 50% but reduces their physical defense to 75%. They will wait a few turns after it wears off before using it again. It will also use Self-Repair to recover HP.
Pantheon's Wrath can be stolen from the Automatons, which deals heavy Lightning damage to all targets. As the Automatons are weak against Lightning attacks, stealing these and using them will work rather effectively, reducing each automaton of nearly 1/4th its health at once. Stealing one from all three and using the three of them will do most of the work in destroying the Automatons for the party. Focus other attacks on the Automatons that have already been stolen from, hopefully destroying them early and limiting the amount of damage that will need to be healed.