Control System Design for Offshore Floating Platform Transportation by Combination of Towing and Pushing Tugboats

Abstract

This study investigates the automated transportation control problem of an offshore floating platform that has limited or no maneuverability. The proposed solution involves two tugboats pushing into the platform and two other tugs towing it in the opposite direction. By implementing cooperative control of these tugs, the desired planar motion of the platform is achieved. For this, the proposed control consists of the following components: (1) an observer estimates the environmental disturbances, (2) a platform motion controller acts as the supervisory control, (3) an optimal constrained allocation distributes the required actions over the tugboats, and (4) the tugboats’ controller derived the control inputs of the tugs to fulfill these requirements. Simulation studies are conducted where the proposed solution is compared to one based on the robust H∞ control framework. The results prove the efficiency and robustness of the proposed system.

Keywords

• <i>H_∞</i> control
• higher-order sliding mode
• offshore platform transportation
• optimal constrained allocation
• tugboat control