Physical A*: Graph-Based Search Algorithm for Robot Navigation On-the-Go

Abstract

Robot navigation is commonly viewed as a trajectory planning problem, relying on a preexisting map. However, the availability of a prior map can be problematic, especially in military or rescue scenarios. This thesis elaborates on the concept of a two-level planning and navigation algorithm called physical A* to address this problem, focusing typically in use cases where a prior map is not known. Physical A* is an A* graph traversal where the robot physically drives along the nodes of the graph. The graph is constructed on-the-go. A lower level planning component proposes multiple waypoints stored as graph nodes. A higher level planner, with a broader understanding of the geographical or spatial context computes the goal heuristic for these nodes. Based on the goal heuristic, the waypoint with least cost is selected to explore towards the goal. Physical A* mainly concentrates on exploring the waypoints that would lead the robot towards the goal in the most optimal form.