Modified Block A<sup>*</sup> Path-Planning Method for Hybrid-Driven Underwater Gliders
Xingaan Liu, Dongli Ma, Muqing Yang, Xinglu Xia, Peixu Guo
Abstract
In this study, a modified Block A <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sup> algorithm is applied to the path planning of hybrid-driven underwater gliders, which combine the buoyancy-driven mode of underwater gliders and the propeller-driven mode of autonomous underwater vehicles, in the ocean environment characterized by strong currents. The objective is to predict a sequence of steering directions and the appropriate driving mode, such that vehicles can minimize their energy consumption to reach the goalregion. In this work, we modify the path generation approach of the original Block A <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sup> algorithm to gain more realistic paths for hybrid-driven underwater gliders and apply an effective energy consumption model in the heap value calculation to find energy-cost optimal paths. Zermelo's function is also incorporated to select the driving mode. The performance of the presented method is then discussed by conducting simulations in three different ocean environments. The results indicate that compared to other methods, the modified Block A <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sup> method avoids local turbulent flow and gains feasible paths for hybrid-driven underwater gliders at a lower energy cost.