Study On 6-DOF Ship Motion Simulator With High-Speed And Heavy Load

The ship motion simulator(SMS)studied in this thesis is a piece of simulation equipment,which can reconstruct the space motion of the ship deck under certain sea conditions in the laboratory environment.The SMS provides the shipborne equipment with a realistic and safe test environment.Compared with the test with active ships,the SMS has outstanding characteristics with high safety,strong controllability,and excellent economy.According to the heavy load,large workspace requirements,a new type of six degrees of freedom(6-DOF)platform with hinge scaling structure,auxiliary support,hydraulic differential driving is designed.The specific research contents of this thesis are as follows:1)According to the requirements of a wide range workspace and high-speed movement,a new 6-DOF platform mechanism with scaling hinge chains is proposed.The 6-DOF platform uses a multi-cylinder driving scaling chain to replace the traditional SPS chain,realizes the high-thrust force and high-speed output of the hydraulic cylinder.2)Cause of the heavy load working environment of the platform,the multi-stage hydraulic cylinder auxiliary support structure and the floating ball mechanism are proposed,and the dynamic modeling of the platform is completed by using the multibody dynamics simulation software ADAMS.By comparing the work condition of the major driving structures with different auxiliary support methods in the typical conditions,the floating ball mechanism is selected as the auxiliary support mechanism of SMS.3)Since the huge power consumption of the high-speed and heavy-load system,the driving characteristics of three kinds of hydraulic double-acting driving cylinders are compared.To reduce the average power consumption of the system,the highefficiency oil supply method of constant pressure which combined the variable displacement pump,the accumulator,and the differential driving actuator is proposed.4)Given the requirement of rapidity and stability of the platform,a nonlinear PID control algorithm(NPID)based on two tracking differentiators(TD)is proposed.The simulation model including control,hydraulic and mechanical is built.Some simulation analysis is carried out for several typical working conditions of the platform,the good responsiveness and stability abilities of the proposed NPID algorithm are verified.