An apparatus for moving the center of gravity of a robot, and a system and method using the apparatus are provided. The apparatus includes a weight conveyor with a conveyed weight weighing a predetermined amount and disposed within the main body of the robot. The conveyed weight is conveyed in a predetermined direction to move the center of gravity of the robot, thus allowing a non-driven caster of the robot to surmount obstacles in its path and not become stuck while the robot is moving.