Self-Righting Characteristic of Autonomous Surface Vehicle Under Intact and Damage Conditions

Abstract In this paper, the concept of self-righting characteristic is introduced into stability analysis of Autonomous Surface Vehicles (ASVs) in order to improve their safety in rough sea. Firstly, the requirements of self-righting characteristic are discussed with the extended GZ curve that covers heeling angle range from 0 to 180 degree, based on the boundary-representation (B-Rep) solid floating body. Then an iteration process is proposed to calculate the righting lever at any heeling angle. With the extended GZ curve for different height of Center of Gravity (CG), the stability surface is created, and applied to compute the curve of extreme height of CG, which is the height limit of CG for ASVs if self-righting characteristic is required. Finally, the damage stability of ASVs is discussed, including how to make ASVs unsinkable, how to treat damage tank/room, how to compute floating state and GZ curve with B-Rep model in damage conditions, and how to analysis the self-righting performances of ASVs with the extended GZ curve etc. An ASV with self-righting hull form is taken as example to illustrate the principles and methods proposed in this study.