Configuration Optimization of Supercavitating Underwater Vehicles With Maneuvering Constraints

Abstract

This paper presents configuration optimization studies on supercavitating underwater vehicles. These innovative vehicles operate at extremely high speeds due to the drag reduction achieved through the supercavitating regime. Their dynamic behavior is complex and highly nonlinear which makes their guidance and control particularly challenging. The extreme performance of the vehicles and the complexity of their dynamic behavior drive the need for an integrated design tool that incorporates operational requirements as part of the design process. This study is a first attempt at optimizing the configuration of supercavitating vehicles, in terms of overall dimensions, mass distributions, and control surfaces size, while accounting for specific requirements related to operation at trim and during maneuvers. The optimization problem is formulated by considering range in straight level flight as the objective to be maximized, and by introducing conditions on trim operation and unsteady maneuvers as constraints. The maneuver requirements are defined by the solution of an optimal control problem, which, for a given vehicle configuration, yields optimal control inputs and corresponding vehicle state time histories. Results are presented to demonstrate the feasibility of the process and to investigate the effect of operational constraints on the final optimal vehicle configuration. The presented methodology considers a limited spectrum of operating conditions, but it is formulated in a way that allows its extension to include a number of such operational constraints, as required by specific mission requirements.