Taking out robot system using roller device

A taking out robot system having a robot configured to take out a workpiece one-by-one by using a hand attached to a front end of a robot arm of the robot, wherein the hand comprises:

• a base part fixed to the front end of the robot arm;
• a gripping part constituted by two or three fingers pivotally attached to the base part, the gripping part being capable of gripping a workpiece to be taken out within a gripping area defined by the fingers;
• a roller device arranged at a front end of each finger, the roller device having a roller driven by a motor,
• wherein the each roller device is configured to grip the workpiece to be taken out between the opposing rollers and withdraw the gripped workpiece into the gripping area, due to forward rotation of the roller,
• wherein the hand further comprises a gripping part-restricting structure configured to gradually varying a distance between the two or three fingers so that a state of the gripping part can be switched between a restricted state in which the fingers are restricted so as to generate a predetermined gripping force and a released state in which the fingers are released from restriction;
• a vision sensor which detects a position and posture of each of a plurality of workpieces which are randomly located;
• a reference motion program which is previously taught in relation to a reference workpiece, the reference motion program including a robot motion command including a series of teaching points and a command for the hand, by which the reference workpiece is taken out by the hand;
• and
• a controller having a function for correcting positional information and postural information at each of the series of teaching points in the reference motion program, based on information from the vision sensor.