Control of underwater robotic vehicles

Underwater robotic vehicles have been very attractive for scientific survey, construction, and maintenance in hazardous environment such as ocean and nuclear plant. The development of advanced vehicle technologies is accelerated by the demand for an underwater robotic vehicle with high performance and efficient operation in terms of time and cost. Most vehicle control systems based on the simplified vehicle model often fail to provide desired performance because of the vehicle´s nonlinear and time-varying dynamics in nature. This paper describes two vehicle controllers: nonlinear controller and adaptive controller considering the effect of thruster dynamics. Results of the controllers tested for the pitch and altitude motion are presented