Controller and control method for collaborative robot

A robot controller configured to control a robot, the robot being configured to perform an operation for a workpiece conveyed by a convey section configured to move in a predetermined convey direction, and being located at a position different from the convey section, the robot controller comprising:

• a robot stop command section configured to output a robot stop command for stopping a motion of the robot when the convey section starts a stop motion,
• wherein the robot stop command includes at least one of:
• a first stop command by which, when a movable section of the robot is positioned anterior to the workpiece with respect to the convey direction, the movable section is moved at a higher velocity than the convey section with respect to the convey direction, and the movable section is stopped after the movable section travels a second coasting distance which is longer than a first coasting distance of the convey section with respect to the convey direction;
• and
• a second stop command by which, when the movable section of the robot is positioned posterior to the workpiece with respect to the convey direction, the movable section is moved at a lower velocity than the convey section with respect to the convey direction, and the movable section is stopped after the movable section travels a third coasting distance which is shorter than the first coasting distance of the convey section with respect to the convey direction.