An efficient magnetic localization system for indoor planar mobile robot

For indoor mobile robot localization, the main objective is to find the robot position, x and y coordinates in its motion plane. Compared with the typical magnetic positioning system having 3 position and 2 orientation parameters, the algorithm can be much simplified if the computation model can be found only on two x and y parameters. In this paper, we present a method by set upping a magnetic transmitting coil over in the robot, while fixing 3-axis sensor coils in a spatial location in the indoor room. Because the height of the transmitting and receiving coils are fixed, and the main axis of the transmitting coil is perpendicular to the x-y plane, the localization problem is simplified to determine two unknown coordinate parameters. By finding the coupling signals between the transmitting and receiving coils, the amplitudes of the AC magnetic sensing signals in a specific frequency are extracted. Then, the robot position parameters are computed by some analytic equations derived from the magnetic dipole model, in which multi-solution and non-positive real solution problems are handled. By using this method, a localization system is built, and the real experiment results show that the localization accuracy is about several decimeters and the execution speed is about 5mS.