Research On Ship Motion Reproduction And Real-time Simulation System

As countries attach importance to the development of marine resources,the exploitation and protection of marine resources has also received more attention.However,disturbed by waves and tides,severe roll,pitch and heave motions have a serious impact on the safety of ship personnel and the stability of shipborne equipment.Therefore,studying the impact of ocean waves on ship motion is of great significance to the stability of marine economic exploitation and the safety of shipping industry.Therefore,this subject studies the wave motion simulation technology in a laboratory environment to 30 tons under 2 levels of ocean waves.As a research background,the passenger ship designed the elbow joint type three-degree-of-freedom wave motion simulation platform to provide simulation platform for shipboard equipment performance test and shipborne equipment dynamic simulation system.Based on the school-enterprise project “Intelligent Logistics Equipment Intelligent Control Platform”,which is jointly established by Jilin University and Jimei University,this paper studies the shipboard equipment dynamic simulation system based on the three-degree-of-freedom platform.The structural design of the hinge position of the upper and lower platforms,the hinge position of the electric cylinder,the length of the upper and lower links,the median height,etc.,and the design of the control system hardware and software,and the difficulty of obtaining the heave displacement are proposed.The Fast Fourier Transform(FFT)algorithm analyzes the spectrum composition of the heave displacement signal online,and uses the Kalman filter algorithm to construct the real-time heave displacement prediction model of the observer,and timely and accurately control the heave motion of the shipborne equipment.The research on the subject of wave compensation has laid a theoretical foundation.The paper mainly completed the work:(1)According to the application background,the structural design of the three-degree-of-freedom wave motion simulation platform is carried out,including the hinge arrangement of the upper and lower platforms,the articulated position of the electric cylinder,the length of the upper and lower links,the median height,the selection of the motor and the electric cylinder.Parameter settings such as type and hinge structure to ensure that the electric cylinder can obtain a larger heave displacement with a small stroke.(2)The Adams software is used to model the structural parameters of the designed shipborne equipment dynamic simulation system.The kinematics and dynamics analysis of the model is carried out,and the force of the electric cylinder is analyzed when the platform moves to a dangerous position.Determine if the structure involved meets the design requirements.(3)The inverse kinematics analysis of the shipborne equipment dynamic simulation system is carried out.According to the position inverse solution analysis,the change of the driving electric cylinder elongation is obtained.The relationship between the speed of the moving platform and the telescopic speed of the electric cylinder is obtained by the inverse analysis of the velocity,which is the design of the control system.Provide the basis.Then the control algorithm of the shipborne equipment dynamic simulation system is designed,the mathematical model of the electric cylinder is established and the transfer function of the system is derived.The composite PID controller with feedback control is adopted as the control strategy of the system,and the Simulink model is established to simulate and analyze the control performance.(4)Aiming at the problem that the ship’s heave motion information is difficult to measure directly,this paper proposes a method based on the combination of fast Fourier transform and Kalman filter to estimate the ship’s heave information.The fast Fourier transform(FFT)algorithm is used to analyze the spectrum composition of the heave displacement signal online,and the Kalman filter algorithm is used to construct the real-time heave displacement prediction model of the observer,and the heave motion of the shipborne equipment can be controlled in time and accurately.(5)The physical construction and experimental analysis of the wave motion simulation platform.Firstly,the hardware facilities of the three-degree-of-freedom shipborne motion simulation system are selected and designed.In the Win7 environment,the software control program is written based on Visual Studio 2013 and Qt 5.8,the flow chart is drawn,and the human-computer interaction interface is written.Secondly,the experimental control of the system’s control precision,wave motion simulation performance and heave displacement information estimation accuracy is carried out to verify the rationality and accuracy of the system design.