This paper presents a play-back navigation for outdoor mobile robots using trajectory tracking method based on environmental magnetic field. Two 3-axis magnetic sensors with horizontal xy-axes opposed to each other, are used to scan magnetic field occurred in the environment to build two different magnetic databases during the teaching stage. In the play-back navigation, the robot rotates 180 degrees and then uses one among the two magnetic sensors readings to perform trajectory tracking based on the magnetic database of another magnetic sensor. The experimental results show that the robot is able to perform the play-back navigation with a reliable accuracy.

This paper describes a trajectory tracking method using environmental magnetic field for outdoor autonomous mobile robots. In this research, a 3-axis magnetic sensor is used to scan DC magnetic field in the outdoor environment to build a database. The robot then performs trajectory tracking based on the database. The experimental results show that by applying the proposed method the robot is possibly able to navigate in the outdoor environment with a reliable accuracy.