Enhancing Exploration in Topological Worlds with Multiple Immovable Markers

The fundamental problem in robotic exploration and mapping of an unknown environment is answering the question 'have I been here before?', which is also known as the 'loop closing' problem. One approach to answering this problem in embedded topological worlds is to resort to the use of an external marking aid that can help the robot disambiguate places. This paper investigates the power of different marker-based aids in topological exploration. We describe enhanced versions of edge- and vertex-based marker algorithms and demonstrate algorithms with enhanced lower bounds in terms of number of markers and motions required in order to map an embedded topological environment.