Robot system and robot control method

A robot control method for a robot system comprising:

• a plurality of robots installed so as to work simultaneously on a common workpiece;
• robot controllers installed corresponding to the robots respectively;
• a plurality of vision sensors configured to acquire visual information;
• and
• a visual processing computer configured to performthat performs processing based on information acquired by the vision sensors,
• wherein the robot control method comprises:
• a first process wherein each of the vision sensors acquires visual information of a measurement target of the workpiece, and transmits the visual information to the visual processing computer commonly used;
• a second process wherein the visual processing computer computes a workpiece coordinate system based on a result of measurement of the measurement target that appears in the visual information received from the plurality of the vision sensors;
• and
• a third process wherein each of the robot controllers transmits a request to the common visual processing computer and corrects a motion of the robot corresponding to each robot controller based on a response received from the visual processing computer, wherein
• the visual processing computer stores information about the workpiece coordinate system with respect to each of the robots,
• the visual processing computer, according to an initialization command transmitted by each robot controller, performs an initialization process on the information with respect to the robot corresponding to each robot controller that transmits the initialization command,
• each of the robot controllers of the robots belonging to a group including two or more of the plurality of the robots to which the workpiece coordinate system is applied, transmits a query to the visual processing computer as to whether the initialization process of the information concerning the workpiece coordinate system has been completed for all the robots belonging to the group,
• if the visual processing computer receives each query in a state that the initialization process of the information on the workpiece coordinate system has not been completed regarding one or more of the robots belonging to the group, the visual processing computer transmits as a response to the query a standby command to each robot controller that queried, and
• each of the robot controllers makes another query to the visual processing computer upon receipt of the standby command.