Controlling the motion of an unmanned underwater vehicle is a challenging task due to the coupled, nonlinear six degrees-of-freedom vehicle dynamics. This motion is exacerbated in underactuated vehicles, as the number of actuators is less than the number of degrees-of-freedom. In this paper a three thruster Remotely Operated Vehicle is considered with the two horizontal thrusters causing disturbance on the pitch, thus creating a large coupling effect that tends to destabilize the vehicle in the vertical plane. Optimization algorithms were used with a nonlinear model to tune PID controllers for depth and heading control in the presence of measurement noise. The results for the depth control show that while the behavior is satisfactory at and around the operating point, it deteriorates further away from that point. An adequate response throughout the operational range is achieved by designing multiple optimized controllers at several operating points and gain scheduling for intermediate points. Finally a fuzzy supervisor was designed to carry out the inferencing based on the operating conditions and a set of rules

Item Type:	Refereed Article
Research Division:	Engineering
Research Group:	Electrical and Electronic Engineering
Research Field:	Control Systems, Robotics and Automation
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in Engineering
Author:	Makavita, CD (Mr Charita Makavita)
Author:	Nguyen, H (Dr Hung Nguyen)
Author:	Ranmuthugala, D (Professor Dev Ranmuthugala)
ID Code:	93370
Year Published:	2014
Deposited By:	NC Maritime Engineering and Hydrodynamics
Deposited On:	2014-07-30
Last Modified:	2015-04-02
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