Prerequisites: Str 13, Improved Sunder, Smashing Style, Weapon Focus with the chosen weapon.
Benefit: While using Smashing Style, if you successfully damage an object with the sunder combat maneuver, you reduce its hardness by 1. An object can’t have its hardness reduced to less than 50% of its normal hardness, and its hardness is restored when the damage dealt by the sunder attack is repaired.
This seems something neat to do against robots. At least a fighter could do something slightly more meaningful with his attacks than hitting for 0 damage due to hardness. And once you reach Hardness 19 your adamantine weapon can go through the full hardness.
The only problem is it reads "An object" and I read somewhere else robots are not objects.
It seems a small effect after so much feat and action economy investment so I guess it would be no problematic to houserule it. But what is the official position on 'robots are not objects' and specifically on 'robots are not treated as objects for feats like Smashing Crush and the like'?
Your biggest hurdle is that you can't sunder a robot. Even if you get past the "is a robot also an object?" (it isn't by the way, a robot is a creature and therefore is treated differently to an object), it is still not "an item held or worn" and therefore not a valid target for sundering.