Abstract—This paper presents a new cooperative object transportation technique with obstacle avoidance. A key idea of proposed technique is to create a corridor around objects by lining up two rows using multiple robots. The multiple robots generate an extended corridor to a goal by following a unified field which consists of a virtual electric dipole field and potential fields. Two pusher robots push the object from behind and two leader robots in front of team lead the robot team to the goal. Simulation results are presented for verifying the proposed technique.