in my humble opinion, if your psychiatrist isn't helping, it may be time to find a new one. This type of behavior isn't helping him to be a productive human being, and if it isn't stopped, then it's only going to get worse as he gets older and stronger. My difficult child was on Abilify, and it didn't help with the same types of behavior your son is displaying. A medication change is definitely in order.
I would also add the police to the mix. The next time difficult child physically hurts you, call the cops. It took a couple of times with my difficult child, but he got the point. He did NOT like being restrained by a cop, nor having to sit in the back of a police car as they took him to the hospital. Now all I have to say when he gets into a rage is that I WILL call the police if he hurts me or damages any property, and he stops. The yelling and screaming doesn't, of course!
My thoughts are with you, and I'm sending you a virtual hug. Take care, keep strong, and know there is support for you here!