Robot exploration in unknown cluttered environments when dealing with uncertainty

The use of autonomous robots in urban search and rescue (USAR) missions has many potential benefits in terms of assisting rescue workers and increasing efficiency in these time- critical environments. However, the cluttered and unknown nature of these environments introduces uncertainty in both the sensing and actuation capabilities of a rescue robot. Such uncertainty has not been directly incorporated into the modeling of the USAR problem for existing robots. In this paper, we present the novel use of a partially observable Markov Decision Process (POMDP) method which directly incorporates uncertainty within the decision-making layer of the controller for a rescue robot. A hierarchical task structure is used to decompose the overall exploration and victim identification task of a robot into smaller subtasks. These subtasks are modeled as POMDPs taking into account sensory and actuation uncertainty. Our proposed approach was tested in numerous experiments in unknown and cluttered USAR-like environments. The results should that the approach was able to successfully explore the environments and find victims, while dealing with sensor and actuator uncertainty.