Mooring Trajectory Planning Of Semi-submersible Support Platform

As humans march into the deep sea,in order to improve the efficiency of resource extraction,the semi-submersible life support platform that provides services and support to marine production platforms or floating production and storage vessels(FPSO)will be gradually put into use.In the process of berthing a semi-submersible support platform to a marine production platform or FPSO,trajectory planning is required.If the berthing trajectory planning is unreasonable,it is difficult to achieve safe escape in some sudden and dangerous situations,and the platform is easy to support.Collision with offshore facilities.In order to ensure the safety of berthing operations,it is important to plan the berthing trajectory of the semi-submersible support platform.This paper relies on the “Deepwater Semi-submersible Support Platform R&D Special Project” of the Ministry of Industry and Information Technology.In order to ensure the safety of the semi-submersible support platform,the berthing scheme is designed and the trajectory planning problem in the berthing process is studied.Mainly completed the following work:Firstly,this paper establishes a semi-submersible support platform mathematical model,environmental disturbance force model and thrust system model with a deepwater semi-submersible support platform as the berthing research object,and introduces the pseudospectral method for solving the optimal problem..Then,for the berthing operation of the semi-submersible support platform,the berthing scheme of segmentation planning for the berthing process is proposed based on the principle of safety as the first principle,taking into account the principle of berthing efficiency,easy operation and economy.In the first stage,the optimal problem performance index with the shortest time as the berth,while considering the obstacle avoidance problem and related constraints in the berthing process,the pseudospectral method is used to solve the optimization problem,and the optimized trajectory is obtained.In the second stage of berthing,taking into account the safety of the support platform when berthing close to the berth,adopting the control strategy of optimistic berthing in the environment,the control support platform follows the set trajectory in the way of optimal environmental orientation.Mooring to the target point.For the first stage of berthing,the pseudo-spectral method is used for trajectory planning.The simulation shows that the pseudospectral method can plan the trajectory that meets the berthing requirement under the corresponding constraints.Then,the berthing scheme of the second stage of the support platform is designed.The environment optimal locating strategy is used to simulate the berthing process of the second stage of the semi-submersible support platform by using the environment optimal positioning controller.experiment.The simulation results show that the semi-submersible support platform can follow the optimal direction of the environment and reach the target point along the set trajectory,meet the requirements of supporting platform berthing planning and verify the effectiveness of the controller.Finally,because the shape of the production platform and the multi-point mooring FPSO are different,especially the support platform should consider the influence of the anchor chain on the berthing path when berthing the FPSO at close range.Therefore,in order to support the platform to berth FPSO,the berthing scheme was designed,and the berthing safety zone was planned by analyzing the distribution of the anchor chain,thus providing security for the berthing of the supporting platform.