Real-time building of a thinning-based topological map with metric features

An accurate and compact map is essential to an autonomous mobile robot system. A topological map represents the environment in terms of the discrete nodes with edges connecting them. It is usually constructed by the Voronoi-like graphs. In this paper the topological map is incrementally built based on the local grid map using the thinning algorithm. This thinning-based topological map does not create the boundary edges and weak meet points which are found in the generalized Voronoi graph. Furthermore, the map can be built in real-time and is robust to the environment change. Since lack of metric data in the topological map poses difficulty in localization, the metric features such as corners are incorporated into the topological map, thus leading to the hybrid map. In this paper the detailed procedure to obtain this hybrid map is discussed and the experimental results are shown to verify the validity of the proposed algorithm.