Machine man is an android robot created by Dr. Abel Stack for US Army. He has given the name X-51 first ang was changed to Machine Man so human can better understand.He has fight with along with Avenger team and has been a reserve member but was revoked after he attacked Firestar and Justice because of Sebastian Shaw's new installed program into him. Source here
image sourceHis powers and abilities includes superhuman strength , durability , stamina , speed and reflexes. When damage he can self repair himself and possesses above human intellect. As a robot he has cybernetic analytical capabilities and can process very fast on processing information. His human name is Aaron Stack, a powered by solar energy but can also get different energy sources.Source here