Modeling and control of a novel over-actuated marine floating platform

Abstract

An autonomous dynamic positioning scheme for a novel triangular floating marine platform is developed, that stabilizes its linear and angular velocities as well as its position and orientation. For this platform, the required closed-loop forces and moments are provided by three rotating pump-jets, located at the bottom of three partly submerged cylinders, located at the corners of the platform. With this control configuration, the platform is over-actuated, i.e., it has more control inputs than degrees of freedom (DOF). Design guidelines leading to balanced actuator loading are identified. A control allocation scheme is developed that allows for station keeping under realistic constraints, disturbances and hardware limitations, without violating thruster dynamics. Furthermore, a model-based controller is proposed that aims at the reduction of fuel consumption. Simulation results, in the presence of realistic environmental disturbances, are presented that demonstrate the performance of the controller and of the allocation scheme developed. Preliminary Hardware-In-the-Loop (HIL) real time experiments are conducted and presented, showing effective platform station keeping.