A method including, when having completed a task with respect to a first coverage region, selecting a support-target robot from within a robot group, which is a plurality of robots capable of communicating with the first robot, starting to cause the first robot to move toward a second coverage region assigned to the selected second robot, and, when the first robot become newly possible to communicate with a third robot from among the plurality of robots while moving toward the second coverage region, determining whether to alter the support-target robot to the third robot, when the support-target robot is determined to be altered to third robot, starting to cause the first robot to move toward a third coverage region that is assigned to the third robot.