Modelling Tunnel Thrusters for Autonomous Underwater Vehicles

Abstract

With 900 Autonomous Underwater Vehicles (AUVs) required over the next decade (Newman et al., 2007) existing survey-style AUVs need improved utilization factors. Additional control devices to extend operational capability need consideration together with the interchange between AUV control approaches. This paper considers supplementary through-body tunnel thruster control during the transition from survey operation to low-speed manoeuvring. Modified manoeuvring equations permit investigation of energy level demands as a positively buoyant AUV is slowed down from cruising speed to maintaining a stationary position. A suitable model of the selected thruster device is proposed following a literature review of tunnel thruster performance.

Model predictive control of a hybrid autonomous underwater vehicle with experimental verification

“…In this description the transient dynamics of the thrusters are not modelled for simplicity, nor the effects of the advance ratio [26].…”

Formalization of design for physical model of the azimuth thruster with two degrees of freedom by computational fluid dynamics methods

“…According to (8), the largest deviation of similarity coefficients occurs in the region of 85-100 % of the rated propeller thrust. The value of corrective factors depending on the propeller flow direction relative to the plane of motion of the ship is within the few hundredths of the percent.…”

“…It is often referred to as the cross-combination of thrusts [8]; -the presence of cavitation for heavy loads on propellers (intake of air) leads to the decrease in pressure on the propeller blades and can occur at low immersion of the propeller due to the motion of ship across the waves [9]; -extreme conditions with large amplitudes of the motion of the ship perpendicular to the surface of water leads to the sudden drop in thrust and torque with the hysteresis effect [10]; -simultaneous reduction of thrust and reverse thrust can occur due to the interaction between the flow from SP and the hull, caused by the effects of pressure, when the small thrust of SP passes along the hull. This is referred to as the Coanda effect [11][12][13];…”

Variable speed hydrodynamic model of an AUV utilizing cross-tunnel thrusters

“…Many of the equations used to develop the three degree of freedom model presented in this paper are simplified equations from the six degree of freedom model developed by [2]. CTT research has been conducted by [1], [3], and [4]. AUV modeling research was pursued by [4], [5], and [6].…”

“…AUV thruster behavior and controllability for a three-state thruster model was analyzed by [10] and applied to the REMUS 100 by [8], and then verified by [1]. Further work on reduced cross tunnel thruster efficiency as an AUV speed increased was published by [3], which was built upon an earlier study by [11], who developed a cross tunnel thruster behavioral model at zero speed of advance in 2007.…”