Prioritized Indoor Exploration with a Dynamic Deadline

Indoor exploration using mobile robots has typically focused on exploring the entire environment without considering deadlines. This paper introduces a priority-based exploration algorithm for situations with an initially unknown and dynamically assigned deadline. The goal of our exploration strategy is to determine the geometric structure of an unknown environment as rapidly as possible and return to the home location. This is necessary for dangerous environments where an initial rapid robot exploration provides critical information about the layout for subsequent operations. For example, firefighters, for whom time is of the essence, can utilize the map generated by this robotic exploration to navigate a building on fire. We present a three-part strategy to solve this problem. First, we represent the physical environment as an exploration graph, whose vertices represent the local environment with its geometric and semantic information. Second, we assign priority values to these vertices based on their environment regions. Third, we present a graph exploration algorithm that employs the vertex priorities. Simulation experiments on a set of graph environments and Gazebo environments demonstrate that, in contrast to prior approaches that ignore the semantic information, our priority-based exploration algorithm enables the robot to efficiently explore more of the environment while satisfying its deadline constraints.