ROBOT SYSTEM FOR COOPERATING A PLURALITY OF ARMS

PROBLEM TO BE SOLVED: To provide a robot system for cooperating a plurality of arms, which does not require changing the specification of a robot even though the dimensions and the weight of a workpiece to be worked are changed. SOLUTION: In a robot system for cooperating a plurality of arms, a plurality of robots 1 having arms 1a which are driven being cooperated, workpiece self- weight compensating device 8 each located at the centers of the plurality or robots 1, being movable in moving ranges in the longitudinal and lateral directions of robot arms 1a of the robots 1. With this arrangement, the dead weight of the workpiece can be supported by the self-weight compensating device 8, and accordingly, no substantial load is exerted to the robots. Thus, the position and the attitude can be precisely controlled. Further, it is not required to change the specification of the robots even thought the dimensions and the weight of the workpiece are changed, except that the self-weight compensating devices are change.