An experimental study of the longitudinal motion control of a fully submerged hydrofoil model in following seas

Abstract

The seakeeping performance of a fully submerged hydrofoil craft suffers in following seas. It is well-known that the sluggishness of the hydrofoil control system is due to the orbital motion of the waves. This paper presents results of a wave-tank study of such a control system applied to a hydrofoil in following seas. The variation of the foil's lift and angle of attack in regular waves are first studied. Then, the experimental model and its control system are re-designed, based on the data gathered in the first phase of the study. The re-design of the control system is based on regulator and Kalman filtering. Results obtained from tank tests of the re-designed system in following seas show that the sluggishness of the control system originated from the orbital motion of the waves. (C) 2003 Elsevier Ltd. All rights reserved.