Design And Control Analysis Of Large Wave Compensated Gangway System

With the advent of the fourth revolution of science and technology and the implementation of Marine Potestatem Strategy,more and more offshore platforms have already been used.The transferring operations of personnel and equipment at sea has also become more frequent between ships and ships or ships and platforms.However,traditional transferring equipment such as transfer baskets and helicopters cannot achieve the objectives of transferring operations of personnel repeatedly due to marine rough weathers and waves.At present,some countries use large wave compensation to board the gangway device for this problem.With an active motion compensation function,large scale wave compensated gangway will make the gangway tip maintain constant with offshore platforms as well as compensate ship motion during transferring process.This paper mainly analyzes and designs the mechanical system and hydraulic system of the gangway,and co-simulating study on the active motion compensation function of the gangway's control system.In order to get reasonable data for simulation and control of gangway operation,the concept design of gangway was determined first,including operational objectives,operational requirements,and operational procedures.The mechanical structure of the gangway was designed by Solidworks software.And then the gangway structure is verified with finite element analysis based on the DNVGL 's technical standards,the calculation results show that the strength and deflection of the gangway meet the requirements.Secondly,presents the mathematical model of gangway dynamics and kinematics based on serial mechanism.Solving the gangway tip position and forward and inverse kinematics solution by coordinate transformation and Denavit–Hartenberg parameters method.Using the Lagrange method expresses the mathematical model of gangway dynamics and calculates the kinetic and potential energy of gangway.Thirdly,presents the three basic hydraulic system of gangway and finds the relation between joint variable and actuator variable.Then a design process regarding how to select proper hydraulic motor,hydraulic cylinders and pump and relative valves will be given.At last,calculates the force,stroke and bore diameter of the pitch and telescopic hydraulic cylinder and builds the AMESim simulation model of the hydraulic system.Finally,determines the control algorithm for the gangway operation.The active motion compensation controller during deployment is based on PID control as well as a position and force control method during transferring operation.Using AMESim and Matlab/Simulink co-simulation method to verify the effectiveness of the active motion compensation.