Optimal Guidance and Tracking Control of Autonomous Underwater Vehicle under Flow Disturbances

Abstract

Numerical solution algorithm for the optimal guidance law of AUV (Autonomous Underwater Vehicle) is presented when it transfers between two pre-designated points in the region of flow disturbances. In the formulation of optimal guidance problem, position vector of the vehicle relative to the inertial frame is qualified as the state vector, while the vehicle's heading as the input. Total amount of time to reach the terminal point is the performance index to be minimized. By solving the optimal guidance law, optimized sequence of vehicle's heading is obtained in time domain, which is to be fed to the heading control system as the reference. Proposed algorithm is applicable to the time-varying flow disturbances as well as time-invariant ones, if only the distribution of them is known a priori. Strategy of optimal guidance with tracking control is applied to the navigation of r2D4, a newly developed AUV by IIS, the university of Tokyo. Effectiveness of optimal guidance law shows its primary dependency on the local distribution of flow disturbances.