Sample-Efficient and Surrogate-Based Design Optimization of Underwater Vehicle Hulls

TL;DR

This paper demonstrates a highly sample-efficient Bayesian optimization method and a DNN surrogate model for underwater vehicle hull design, achieving two orders of magnitude speedup with comparable accuracy to CFD simulations.

Contribution

It introduces the first application of Bayesian optimization and DNN surrogate modeling to UUV hull design, improving efficiency and transferability in CFD-based optimization.

Findings

BO-LCB is the most sample-efficient optimization method tested.

DNN surrogate model predicts drag force with 1.85% MAPE.

Two-orders-of-magnitude speedup in design optimization process.

Abstract

Physics simulations like computational fluid dynamics (CFD) are a computational bottleneck in computer-aided design (CAD) optimization processes. To overcome this bottleneck, one requires either an optimization framework that is highly sample-efficient, or a fast data-driven proxy (surrogate model) for long-running simulations. Both approaches have benefits and limitations. Bayesian optimization is often used for sample efficiency, but it solves one specific problem and struggles with transferability; alternatively, surrogate models can offer fast and often more generalizable solutions for CFD problems, but gathering data for and training such models can be computationally demanding. In this work, we leverage recent advances in optimization and artificial intelligence (AI) to explore both of these potential approaches, in the context of designing an optimal unmanned underwater vehicle (UUV) hull. Our study finds that the Bayesian Optimization-Lower Condition Bound (BO-LCB) algorithm is the most sample-efficient optimization framework and has the best convergence behavior of those considered. Subsequently, we show that our DNN-based surrogate model predicts drag force on test data in tight agreement with CFD simulations, with a mean absolute percentage error (MAPE) of 1.85%. Combining these results, we demonstrate a two-orders-of-magnitude speedup (with comparable accuracy) for the design optimization process when the surrogate model is used. To our knowledge, this is the first study applying Bayesian optimization and DNN-based surrogate modeling to the problem of UUV design optimization, and we share our developments as open-source software.