Autonomous Navigation of Quadrupeds Using Coverage Path Planning with Morphological Skeleton Map

--This paper proposes a novel method of coverage path planning for the purpose of scanning an unstructured environment autonomously. The method uses the morphological skeleton of the prior 2D navigation map via SLAM to generate a sequence of points of interest (POIs). This sequence is then ordered to create an optimal path given the robot's current position. T o control the high-level operation, a finite state machine is used to switch between two modes: navigating towards a POI using Nav2, and scanning the local surroundings. We validate the method in a leveled indoor obstacle-free non-convex environment on time efficiency and reachability over five trials. The map reader and the path planner can quickly process maps of width and height ranging between [196,225] pixels and [185,231] pixels in 2. 52 ms and 1 . The robot managed to reach 86. 5 % of all waypoints over all five runs. The proposed method suffers from drift occurring in the 2D navigation map. Due to advancements in technology and miniaturization, in the past decade surface (or ground) robots, such as wheeled and legged robots, have been increasingly adopted for diverse operations in harsh and unstructured environments. One of the key challenges in such environments is that the infrastructure to support diverse operations does not readily exist. These environments include, for example, disaster response [1], [2], [3], mining operations [4], [5], space exploration [6], [7], [8], [9], surveillance in remote locations [10], [11], or hazardous industries like nuclear power plant maintenance [12], [13]. In such complex environments, legged robots are more versatile and robust compared to wheeled robots than other surface robots such as wheeled rovers, and can adaptively navigate uneven, rugged, or soft terrain. Legged robots can cover relatively larger spatial areas by choosing safe footholds within their range of motion and rapidly responding to adjust their kinematic configuration [14] to achieve their objectives. The number of legs in a legged robot determines its movement efficiency and ability to maintain stability [15]. The source code is open source and is available at: https://github.com/ On the other hand, quadrupeds possess simpler structures and control mechanisms than hexapodal and octopodal robots [16], [17]. For this reason, quadruped robots are ideal for tasks involving safe navigation of complex 3D environments for (sub-)surface exploration.