A method, performed by a cleaning robot, of performing a task, is provided. The method includes capturing an image of an object in a vicinity of the cleaning robot, determining a task to be performed by the cleaning robot, by applying the captured image to at least one trained artificial intelligence (AI) model, controlling a guard portion to descend from in front of an opened portion to a floor surface of the cleaning robot, according to the determined task, and driving towards the object so the object is moved by the descended guard portion.