Design Of Dynamic Positioning System For Sandglass-type Floating Platform

With the increasing water depth of marine development operations,dynamic positioning systems have important engineering value for deep-sea vessels and platforms.A new concept deep-sea sandglass-type floating platform has recently been proposed to address the performance limitations of conventional ship and cylindrical FPSO/FDPSO for deep-sea floating platforms.The predecessor has carried out detailed research on the platform from the aspects of structural optimization,strength check and mooring,but no one has studied the dynamic positioning system of the platform.Therefore,combined with the research results of the dynamic positioning system and the hydrodynamic characteristics of the sandglass-type floating model,this paper will mainly study and design the dynamic positioning system of the sandglass-type floating platform.(1)The monitoring system in the sandglass-type platform dynamic positioning system is studied.Based on the Kalman filter technique and the hydrodynamic parameters of the sandglass-type floating body model,a dynamic model suitable for the sandglass-type floating ocean platform is established.On this basis,the effects of process noise and observed noise on the Kalman gain value are discussed.The analysis of the proposed filter model has good effects in noise filtering and motion separation.(2)Combined with the shape characteristics and positioning index requirements of the sandglass-type platform,the design of the thrust system is carried out.The type,transmission strategy and layout scheme of the thrust system are mainly discussed.The flow field and open water performance of the propeller are simulated based on the CFD numerical model and algorithm.The pitch ratio is preferably 1.0 depending on the quality factor.On the basis of the analysis,the interference of the thrust system is analyzed,including the thruster and transmission,and the interference between the floating body and the thruster.Through numerical simulation,it is found that the transmission has little effect on the running performance of the propeller.In addition,the two thrusters have obvious interference when they are in the same straight line.As the distance of the propeller increases,the thrust loss rate gradually decreases.(3)Based on the open water performance and interference effect of the new propeller,combined with the hydrodynamic characteristics of the sandglass-type floating body,the time-domain simulation of the thruster dynamic positioning is carried out.In the dynamic positioning simulation process of the sandglass-type floating platform,based on the PID control model,the interference between the thruster and the floating body is curve-fitted in the thrust system distribution scheme,and the lowest energy consumption is obtained.The standard objective function and the corresponding constraints are finally distributed to the total thrust by the penalty function method,and then the time-domain numerical simulation of the characteristics of the sandglass-type floating platform dynamic positioning system is realized.(4)Based on the above research on dynamic positioning strategy and algorithm of sandglass-type floating platform,the hardware construction of dynamic positioning system is studied.First,the structure,working principle,driving technology and software and hardware systems of the RapidECU control system are studied.Then,based on this,the real-time control research of stepper motor,servo motor and sensor is carried out respectively.According to the sensor input and motor output,a complete control idea is proposed,which is the power of the sandglass-type floating platform in practical engineering.Provide reference for the design and construction of the positioning system.