Research On Design And Control Strategy Of Marine Shock Absorber Performance Test Bench

As an important part of ship equipment,rubber shock absorber can restrain vibration generated during ship motion,improve instrument precision and protect mechanical equipment.Its performance is related to safety and stability of ship operation.Shock absorber performance test bench is the most effective way to test the performance parameters of rubber shock absorber,and more and more attention has been paid to it.In this paper,a vibration shock absorber performance test bench based on servo cylinder is developed,and a force position control strategy is proposed to realize the static and dynamic parameters test of the marine shock absorber.The specific work done is as follows:(1)The function and performance index of the performance test bench of the marine rubber shock absorber are analyzed,and the performance test bench of the marine shock absorber is designed according to the following requirements: under the static loading condition,the system is able to load the rubber shock absorber to the specified load in order to complete the static stiffness and creep test of the rubber shock absorber;Under the dynamic loading condition,the system firstly loads the rubber shock absorber to the rated load,then takes this position as the zero point and make the deformation of the rubber shock absorber follow the specified sine curve to complete the dynamic stiffness test of the rubber shock absorber.Finally,the design scheme of performance test bench for marine shock absorber driven by servo motor is determined.Through the analysis of rubber shock absorber,servo motor and electric cylinder,the overall mathematical model of the system is finally obtained.(2)The idea of multi-closed-loop control is introduced and a three-closed-loop control structure is constructed,in which the inner loop is current loop,the middle loop is speed loop and the outer loop is load force/position loop.The outer loop of loading force realizes fast and accurate output of static force.The position loop tracks the specified sine curve.In order to improve the smoothness of the system,a smooth switching function is constructed to deal with the signal jump caused by controller switching in dynamic test.Finally,through simulation analysis,the influence of system parameter changes on system stability and dynamic responses are studied.The simulation results also verify the effectiveness of the force position control strategy proposed in this paper.(3)The performance test bench of marine shock absorber is established.According to the system performance requirements and design indexes,the equipment selection for the designed test bench is completed,and the lower computer control program and the upper computer human-machine interface are developed.The validity of the designed control strategy is verified by static stiffness,creep and dynamic stiffness test of rubber shock absorber.