Self-Localization of Mobile Robots Based on Visual Information

A CCD camera, a stepping motor and three artificial landmarks are used for localization of a mobile robot. The CCD camera is mounted on the robot and its rotation is controlled by the stepping motor. Then from the images captured by the CCD camera, image-processing techniques are used to determine the distances between the CCD camera and the three landmarks. On the basis of these distances, one can prove that the position of the robot can be determined uniquely provided that the three artificial landmarks observed are not installed in a line. Moreover, the heading angle of the robot can be determined from the rotation angle of the stepping motor. To account for possible installation errors, a nonlinear programming method is proposed. Meanwhile, a least-squares method is also be used to increase the accuracy of localization. To show the feasibility of the proposed method, an experimental example is given for illustration