Research On Impact And Coupling Distraction Suppression Method Of Load Sensing Hydraulic System

Load sensing hydraulic system is widely used in engineering machinery,construction,agriculture and other fields due to its advantages of good flow adaptation,small overflow loss and throttling loss,and energy saving.The pressure impact caused by the frequent opening and closing of the flow control valve in the system and the coupling distraction between the loops directly affect the reliability and stability of the system.Therefore,it is significant to study the pressure impact and coupling distraction of the system.This paper targeted the load sensing hydraulic system,established the pressure flow equation in the pipeline between the pump and the flow control valve,the cause of pressure impact in the load sensing hydraulic system and the influence factors on the peak value of the impact pressure was analyzed.An anti shock loop was set between the flow control valve and the pump to suppress the pressure impact.Based on AMESim software,the simulation model of load sensing hydraulic system was established.The factors affecting the peak value of impact pressure in load sensing hydraulic system were compared and studied,and the simulation also studied the effect of anti shock loop on the pressure impact in the load sensing hydraulic system.A load sensing hydraulic system test rig was developed,and the theoretical analysis and simulation results were verified.Further,the mathematical model of multi-actuators load sensing hydraulic system was established.The cause of coupling distraction between the loops of multi-actuators load sensing hydraulic system was analyzed,and the influence factors of coupling distraction was analyzed.The anti shock loop was set to suppress the coupling distraction.A simulation model of a single pump and dual motors load sensing hydraulic system was established.The affects of hydraulic pump performance parameters,operating parameters,pipeline parameters,and initial working flow of the unclosed loop on the coupling distraction were studied,the effect of the anti shock loop on reducing coupling distraction between loops was studied,and the impact of anti shock loop on the response characteristics of systems under different valve switch signals.The research results show that the fundamental cause of pressure shock and coupling distraction in the system is that the change in pump outlet flow lags behind the change in flow control valve flow,leading to an increase in net flow in the pipeline between the hydraulic pump and flow control valve.The larger the hydraulic pump displacement,the longer length between the pump and the flow control valve,the longer the closing time of the flow control valve,the larger the initial working flow rate of the unclosed loop,the smaller the peak impact pressure at the outlet of the hydraulic pump the coupling distraction between the loops.The anti shock loop can suppress the pressure impact,and reduce the coupling distraction with the multiactuators work.Flow control valve switch signals for square wave or sine signals under frequent opening and closing,the load sensing hydraulic system with multi-actuators installed with anti shock loop has high stability and good response characteristics.