when doing a character model you add bones to the one piece character model and the bones are used to move and pose the model after they are merged.

 

What about something like a robot or a mech.  The mech has more than one piece.  Is there a way to connect a leg to a hip and then adjust the constraint settings for movement?  I wouldnt import all the pieces into the modeling area until the robot is all one piece then add bones?   It seems like that would make the parts morph out of shape....

is there a command that allowes me to connect multiple parts then set the contraints like bones?