Terrain map building for a walking robot equipped with an active 2D range sensor

This paper deals with problems of rough terrain perception and mapping for walking robots equipped with inexpensive optical range sensors providing 2D data only. Two different sensing modalities are considered: the structured light sensor, and the Hokuyo URG-04LX laser scanner. Measurement uncertainty in both sensors is taken into account, and different geometric configurations of these sensors on the walking robot are analysed, yielding the configurations that are best for the task of terrain perception. Then, application of the acquired range data in local terrain mapping is presented. The mapping algorithm as well as novel methods for removing map artifacts that result from qualitative errors in range measurements are detailed. Experimental results are provided.