Visual servo tracking control of a wheeled mobile robot with a monocular fixed camera

Abstract

A visual servo tracking controller for a wheeled mobile robot (WMR) is developed that utilizes feedback from a monocular camera system that is mounted with a fixed position and orientation (i.e., the eye-to-hand problem). A prerecorded image sequence (e.g., a video) of four target points is used to define a desired trajectory for the WMR. By comparing the target points from the prerecorded sequence with the corresponding target points in the live image, projective geometric relationships are exploited to construct a Euclidean homography. The information obtained by decomposing the Euclidean homography is used to develop a kinematic controller. A Lyapunov-based analysis is used to develop an adaptive update law to actively compensate for the lack of depth information required for the translation error system. In contrast to previous WMR visual servo controllers using a fixed camera configuration, the controller in this paper does not require the camera to be mounted so that the optical axis is perpendicular to the WMR plane of motion.