Dynamic analysis and optimal control of the landing process of the offshore installation

Abstract

During the offshore installation process, any disturbance such as heave motion may lead to a significant impact on the equipment, which may damage the equipment permanently. The shock isolator for the installation can provide good performance for the equipment and has the ability to adapt to various ocean conditions. Therefore, an experimental facility of offshore installation is set up, and the dynamic model is presented. The model includes the effect of the tensioning and relaxing of rope and the displacement constraint of shock isolator. Considering the maximal travel range of the isolator finalized as a constant force isolator, the optimum control strategy is conducted to mitigate the peak force transferred to the equipment during the landing process. Finally, the experimental results are compared to the simulation results under typical operating conditions. Then, the effective of this optimum strategy can be verified by comparing the passive control strategy. It can be found that when the optimal control strategy can reduce the peak acceleration of equipment under the harsh sea condition.