Cooperative consensus control applied to multi-vessel DP operations

With the increasing deep water oil & gas exploration, there is also an increase of the demand for offshore operations involving multi-vessels. Such operations require high level planning and coordination, which in most cases occurs by information exchange at the operation level, being each vessel commanded independently. Examples of such operations are offloading, subsea equipment installation and research operation, always involving multiples dynamic positioned (DP) vessels. The advantage of the cooperative control arises with the reduction of the relative positioning error during station keeping or transient maneuvers. In this work, consensus control concepts are applied combined with the DP System of each ship. The cooperative DP controller will be investigated with the analysis of the coupled dynamics of the vessels. The influence of cooperative control gains on the whole system will be discussed, using the frequency response of the open loop system. Fully nonlinear time-domain simulations and experimental results will be used to demonstrate the operation of cooperative control. Besides that, comparisons between the small-scale experiments and equivalent numerical simulations will be carried out, validating the numerical's results. The adopted design requirements are also demonstrated to be met.