A method for an autonomous mobile robot to recognize its position in the global coordinate system when building a map

Abstract

A method is presented for an autonomous mobile robot to recognize its position when building a map of its environment. In conventional map building methods, it is difficult to build the map accurately in the global coordinate system, simply because the robot cannot know its exact position in the coordinate system after some movement from a known position. With the proposed method, however, two robots are used to recognize their positions. When one of them moves to another place, the other observes the move and determines the new position exactly. In this way, each robot observes the other, and the observed position information is exchanged. Consequently, both robots always known their exact position. This paper first presents, the principle of the proposed method. Then, an additional method is presented for two robots observing each other's position. Finally, the recognition error regarding a robot's position after long-distance movement is estimated.