Angular rate-constrained path planning algorithm for unmanned surface vehicles

Abstract

This study suggests a new approach based on Theta* algorithm to create paths in real-time, considering both angular rate (yaw rate) and heading angle of unmanned surface vehicles (USVs). Among the various path planning algorithms, a grid map-based path planning algorithm has frequently been employed for maintaining the control stability of nonholonomic USVs. This algorithm is powerful in that it generates a path with the fastest computation time. Most path planning algorithms for the ocean environment, however, have only been performed on an Euclidean group SE(2) grid map with no considerations of the vehicle performance. Other path planning algorithms for an SE(3) grid map generate resultant paths with consideration of vehicle heading, but most of them do not operate in real-time. Moreover, these algorithms always generate constant angle at each orientation node, and the size of graph must be expanded to provide finer angular resolution. To solve these problems, the angular rate-constrained Theta* (ARC-Theta*) is proposed to create paths in real-time with considerations of vehicle performance on the SE(2) weighted occupancy grid map. The performance of this proposed algorithm is verified with simulations and experiments. The results showed that the ARC-Theta* algorithm is effective for global path planning of USVs.