Mobile robot localization using color signboard

Accurate, flexible and low-cost localization is an important issue for achi eving autonomous and cooperative motions of mobile robots. This paper propo ses a localization method for indoor mobile robots by using vision and arti ficial signboard. The signboards are placed in an environment and attached to the robots to decide the absolute positions and relative positions, resp ectively, of the robots. The important contribution is using signboard for the relative localization. Use of forward-looking camera and eye-level sign board allows us to achieve both the absolute and relative localization in a multi-robot environment, however, it brings a potential problem that the s ignboard viewed with the camera tends to be occasionally occluded with mobi le robots hovering in the environment. The signboard is therefore designed such that the forward-looking camera can reliably detect the signboard even though it is partially blocked with unforeseen obstructions. A color-codin g pattern is printed on the signboard to identify a lot of signboards in th e multi-robots environment. The Kalman filter and the Interacting Multiple Model method are applied to find accurate positions of the robots by using the identified signboards. Experimental results show the feasibility of the proposed localization method. (C) 1999 Elsevier Science Ltd. All rights re served.