The performance of vertical tunnel thrusters on an autonomous underwater vehicle operating near the free surface in waves

Description/Abstract

When operating near the free surface in waves, underwater vehicles can experience large forces acting on the body which can cause the vehicle to move undesirably. To overcome these forces, and keep station with minimal disturbance, actuators fitted to the vehicle are used. To develop a suitable controller, the performance of said actuators must be known. This paper shows that as a vertical tunnel thruster approaches the free surface, the thrust generated decreases. Experimental and simulated data is presented and reasons for the reduction in effective thrust discussed. Further to this, the performance of the Delphin2 AUV operating in waves is analysed and suggestions made for improving performance.