Optimal control of an autonomous underwater vehicle equipped with the collective and cyclic pitch propeller

This paper aims to develop an optimal state feedback controller using the Linear Quadratic Regulator for an autonomous underwater vehicle equipped with an innovative collective and cyclic pitch propeller. This new type of propulsion system offers advantages such as good manoeuvrability for the torpedo shaped underwater vehicle at low speed operations. To develop the linear controller, the underwater vehicle general equations of motion are decoupled into non-interacting longitudinal and lateral subsystems in the form of linear state space models. The vehicle hydrodynamic coefficients and the propulsor dynamic model are derived using the system identification method and experiments in the towing tank. The control objectives are to maintain the autonomous underwater vehicle at desired depth and heading with the newly developed propulsor. The performance of the controller is demonstrated by simulation using MATLAB/SimulinkTM. The results show that the designed controller gives good performance and effectiveness in which the vehicle is able to follow the reference input signals.