System identification of porpoising dynamics of high-speed planing craft using full scale trial data

Abstract

Porpoise, a coupled heave and pitch oscillation, is one of the unstable behaviors in high-speed planing craft. To suppress porpoise, drivers respond by reducing the speed of the vessel. Active control using trim tabs has also been studied in the past. In order to suppress porpoise by actively controlling the trim angle of the outboard motor, this study develops a suitable motion model for this control. The following were studied in this paper: (1) a numerical motion model running straight for a planing craft with an outboard motor was proposed; (2) a method to identify the motion model based on the actual test results was proposed. In this paper, we conducted system identification based on experimental data using a representative craft. Accordingly, identification results that reproduced the occurrence of porpoise were obtained.