Chappie doesn't move like a robot

he learns everything from the people around him. the scouts were generally very mobile as they were fighting crime (i.e. the jump one of those made while pusuing hippo) so the abillity to move in all kind of ways was in their hardware, it was just unnecessary to walk around with hand on hip etc. chappie did all these to fit in with the gang. it was the kind of experiences he had.
having said that i don't disaggree that it might have been an actor with cgi, i am simply saying why it was not out of character.

It is funny that this corporation ("transtellar" or whatever) built these robots that are like 100 years ahead of everything else in the current movie world. Check for instance the nerds house. Full of ancient droids that move like crap. Technologically nothing else in the movie world comes even close to those police-androids.