Multivariable optimal control of an autonomous underwater vehicle for steering and diving control in variable speed

Abstract

This paper describes a multivariable optimal control for a Semi-Autonomous Underwater Vehicle (SAUV) developed in Korea Ocean Research and Development Institute (KORDI). The SAUV is a test-bed for evaluation of navigation algorithms and manipulator technologies for a mine disposal vehicle (MDV) in military use and for a light working underwater vehicle in scientific application. The vehicle was designed to control its cruising speed, heading and depth with 4 horizontal thrusters installed at the rear of the hull. The decoupled control methods are limited to be applied to the SAUV because the thrust forces are highly coupled with the surging, yawing, and pitching motion of the vehicle. The multivariable Linear Quadratic (LQ) control method is chosen to control steering and diving in variable speed motion automatically. This paper presents the results of tank-test with the controller and compares them with the simulation results to validate the performance.