Design And Simulation Of Active Wave Compensation System For Three-DOF Gangway Device

With the proposal of the maritime power strategy and the development of marine equipment,scientific and technological competition between countries is gradually unfolding in the maritime field.The utilization of marine resources has also become a value trend.In order to carry out maintenance work and transfer work normally in the ever-changing and dangerous marine environment,it is necessary to be able to build a stable channel between the offshore platform and the ship.The gangway is just such a device.The gangway can compensate for the movement of the end of the gangway caused by the disturbance of sea waves by controlling the rotation of the three joints,maintain a stable connection between the end and the platform,and ensure that the normal work of the staff has economic value.And engineering meaning.In the process of researching multi-degree-of-freedom motion compensation devices,domestic research started from the compensation of heave motion between the ship and the platform,but the research on multi-degree-of-freedom gangways is relatively small and mainly concentrated on the theoretical research level.This article introduces the related concepts of random waves,and uses the open source MSS toolbox to simulate the six-degree-of-freedom motion of the marine supply ship,simulating a more realistic marine environment;using the DH parameter method commonly used in industrial robot modeling to define the parameters of each joint,The projection of the end of the gangway under the frame of the bridge base is obtained,the forward and inverse kinematics solves the functional relationship between the joint variables and the end trajectory variables,and the Jacobian matrix defines the given trajectory speed and the end of the gangway.The conversion relationship between joint speeds;for the specific gangway,design the hydraulic control system of the gangway,calculate the specific parameters of the hydraulic cylinder and the servo valve,derive the open loop electrohydraulic servo transfer function,and analyze the three joints Dynamic characteristics;the rotary joint focuses on compensating the impact of load disturbance on the end trajectory,and the active disturbance rejection controller is designed to effectively compensate for the load disturbance;the pitch joint focuses on the robustness of the system,that is,it can still maintain stability under the condition of internal parameter perturbation,The design of robust H∞controller has a good simulation effect to ensure that the system remains stable;the telescopic joint focuses on the contact force with the platform,and the force-position parallel controller is designed so that the end is always against the platform;when the gangway is mounted on the platform,establish the coordinate system of the bridge system,analyze the influence of wave disturbance on the end of the gangway,and design a feedforward feedback composite controller.Taking the bow motion as an example,the simulation results show that the addition of the feedforward controller makes the system more responsive.The fast steady state error is smaller.In this paper,the random wave disturbance is the main disturbance,the corresponding relationship between the coordinate system of the gangway and the ship following coordinate system is established,and the influence of the wave disturbance on the end of the gangway is calculated.The joints of the bridge crossing device are controlled to move in the opposite direction of the disturbance to compensate for the disturbance of the sea waves.The gangway is divided into two parts:the deployment phase and the connection phase.The controllers are designed for the two research phases.The simulation results verify the correctness of the controller.Taking specific products as the research object has practical application value.The research provides a theoretical basis.