ROBOT ARM STRUCTURE

PURPOSE:To eliminate the necessity for a drive means in each articulation by forming the first articulating means to serve as a passive articulation and the second articulating means to serve as an active arm, and driving the first articulating means by power input through the second articulating means, in a robot arm structure used in a process or the like of manufacturing an automobile. CONSTITUTION:In case of assembly work, first a brake mechanism of the first passive articulation 7 is turned off, to control a position of a main unit side arm 4, and while holding a horizontal condition of the arm, an active articulation 5 is moved right downward. A workpiece 3 held to a hand 11 is brought into contact with a floor panel 12 of a vehicle body 2, to impede moving the hand 11 downward, and successively, the hand 11 and the workpiece 3 are turned clockwise around the passive articulation 7. Next, when the second passive arm 10 is placed in a position parallel to the floor panel 12, moving the active articulation 5 is stopped, and this active articulation 5, after it is rotated again clockwise, is moved leftward, to bring the workpiece 3 fixed to a front part prescribed position of the body 2.