Heading control of an underwater vehicle

Abstract

In this thesis an overview of Autonomous Underwater Vehicles (AUV) is presented which covers the state of art in AUV technology, different components such as sensors and actuators of AUV and the applications of AUVs. This thesis describes the development and verification of six degree of freedom, non-linear simulation model. In this model, external forces and moments are defined in terms of vehicle coefficients. A nonlinear model of AUV is obtained through kinematics and dynamics equations which are linearized about an operating point to get a linearized horizontal plane model. The objective of the AUV control here is heading control i.e. to generate appropriate rudder angle position and thrust so that the desired heading is achieved.
For the above heading control we develop a controller that consists of two loops, one is controlled by a PD controller and the other loop by a P control action. The first and second order Nomoto model of the vehicle is formulated and studied for simpler qualitative analysis of complicated ship model.
Simulation studies were undertaken also for yaw control of a single AUV. The above controller is designed for effective tracking of desired trajectory of the AUV in horizontal plane. All the simulations were performed using both MATLAB and SIMULINK.
The results obtained for heading and yaw control of the AUV studied are presented and discussed in this thesis.