Numerical Simulation Of The Motions Of One DP Vessel Using PID Control Algorithm Considering The Failure Of One Propeller

In the area of the exploitation of ocean resources, such as oil, nature gas and wind energy, it is important for the vessel to maintain the position on the ocean. In the traditional method, the mooring system is used to maintain the vessels at desired position. This system may be unsuitable for deep-water areas on the ocean, however the vehicles with the dynamics positioning system can be meet the requirement of the exploitation of the ocean resources. The vessel with DP system can save more time to arrange the mooring lines, so the DP systems are widely used for the depth-water vessels. The motions of the vessel would be violent for some sea states and there are some limitations for the works of the vessels. For the safety of the operating vessel, it is important to research and to simulate the motions of the ship with dynamics positioning systems.There are a lot of studies and applications of the dynamics positioning system and control algorithms. The SESAM software and SIMO code are used to simulate the motions of the motions of the vessel with DP system in this paper. The PID algorithm is used to control the position of vessel. The results of the motions are used to evaluate the position system of the vessels. The fail of the propellers are also considered in the simulations. The results of the simulation are separated into wave frequency and slow-drift components using FFT method. These two components are used to analyse the statistical motions in different frequencies. The guide notes of DNV's rules are used to evaluate the positioning system of the vessel.The statistical motions can be used to choose the suitable sea states for the operating vessel. The results can be regarded as a reference for the real works of the vessel on the ocean.