Cooperative Cable-Suspended Maritime Salvage Using Multiple Unmanned Helicopters with Prescribed-Performance Position Tracking

Cooperative maritime salvage using multiple unmanned helicopters involves coupled cable forces and changes in seabed suction, hydrodynamic drag, and buoyancy. This paper studies helicopter position tracking during seabed release, underwater lifting, partial emergence, and aerial transport. A simplified coupled dynamics model is combined with finite-time prescribed-performance control (FPPC) and an unknown system dynamics estimator (USDE). The performance boundary reaches a prescribed final value at a user-selected time, while the estimator reconstructs lumped cable-induced disturbances for compensation. The control structure includes position, velocity, attitude-angle, and angular-rate loops. Numerical comparisons with DSC-USDE are conducted for cuboid and cylindrical payloads. The archived controller-error records indicate smaller tracking errors and improved performance-boundary retention in the considered nominal scenarios. These results provide a numerical assessment of the proposed controller within the assumed simulation model; they do not constitute experimental validation of the complete physical salvage system.