Position control of crane vessel during offshore installations: Using adaptive and robust control methods

Robustifying Dynamic Positioning of Crane Vessels for Heavy Lifting Operation

“…For construction vessels such as dredgers, heavy-lift vessels, and pipe-laying vessels, additional uncertainties arise: in particular, uncertainties from unmodelled dynamics of the propulsion system and unmodelled forces become crucial during offshore heavy lift operation (see Figure 1). Unmodelled dynamics of the propulsion system affect the precision of the DP system, since the propulsion system of a vessel cannot provide a fast response against disturbances induced by waves or measurement noises [3]; also, studies have shown that unmodelled forces propagating through the crane wires during heavy lifting operation (such uncertainties are commonly referred to as mooring forces) can cause unstable oscillatory behavior of the DP system [8,9]. These uncertain scenarios bring challenges in the design of DP systems, which are of high interest due to the hazard during offshore heavy lifting operation.…”