Localization Using Magnetic Patterns for Autonomous Mobile Robot

Abstract

In this paper, we present a method of localization using magnetic landmarks. With this method, it is possible to compensate the pose error (x e , y e , θ e) of a mobile robot correctly and localize its current position on a global coordinate system on the surface of a structured environment with magnetic landmarks. A set of four magnetic bars forms total six different patterns of landmarks and these patterns can be read by the mobile robot with magnetic hall sensors. A sequential motion strategy for a mobile robot is proposed to find the geometric center of magnetic landmarks by reading the nonlinear magnetic field. The mobile robot first moves into the center region of the landmark where it can read the magnetic pattern, after which tracking and global localization can be easily achieved by recognizing the patterns of neighboring landmarks. Experimental results show the effectiveness of the sequential motion strategy for estimating the center of the first encountered landmark as well as the performance of tracking and global localization of the proposed system.

Two-Dimensional Position Tracking Using Gradient Magnetic Fields

“…The positioning accuracy achieved in our work is generally better than the existing magnetic-field-based methods reported for three- or two-dimensional position tracking [ 23 , 24 , 25 ]. For instance, the magnetic positioning of the capsule endoscope using an array of 16 three-axis Hall sensors and a magnetic tube is reported in [ 23 ], in which the random complex algorithm (RCA) gave better results than the Levenberg–Marquardt algorithm (LMA).…”

“…The experimental results show that the root mean square error (RMSE) for the estimated position value of the permanent magnet was less than 1.13 mm in the X, Y, and Z directions. Another example is the position-tracking system using magnetic landmarks for autonomous mobile robots with the estimation method using NVM (Neutral Magnetic Valley) [ 24 ]. For this method, the positioning errors are generally less than 3 mm in the 130 mm range of a single cell.…”