Research On Effect Of The Inerter On Vehicle System Stability

As people’s requirements for vehicle running stability gradually increase,traditional passive suspension parameters cannot be adjusted after being determined,so their performance cannot meet the requirements of future development.Although the running stability of active suspension and semi-active suspension in recent years have improved,its disadvantages such as high cost,large energy consumption and control with time lag have limited its application and promotion.So the better passive suspension structures may have better development.Therefore,in this paper,the inerter is used as the damping element of the passive suspension system to study the vehicle running stability from the vertical vibration of the train.The theoretical analysis and computer simulation calculation are used to analyze and study the vertical vibration dynamic performance of the vehicle.This paper considers introducing the two-stage series inerter-spring-damping(ISD)passive suspension mechanical model into a traditional rail vehicle model to establish an improved model.Based on Newton’s second law,differential equations to build the system,and the differential equation of system motion is transformed into matrix form for subsequent vehicle system simulation analysis.The input excitation of the system adopts the irregular six-level orbit of the United States,and the vibration response of each part of the system is calculated by a combination of time domain and frequency domain.In the time domain,Matlab / Simulink simulation is used to obtain the time history response diagram of each part of the vehicle system.Then compare and analyze the impact of vehicle speed,suspension parameters of the first series shock absorber and the two-stage series ISD shock absorber on the time domain response of the vehicle system.The time domain responses of traditional passive suspension system,ISD passive suspension system,and two-stage series ISD passive suspension system are analyzed and compared.The study found that within a certain range the vehicle speed was positively correlated with the vibration response of the vehicle body.The suspension parameters of the second series shock absorber have a greater impact on the vertical vibration of the vehicle,the two-stage series ISD passive suspension system has a greater improvement in vehicle time domain response than the other two systems.In the frequency domain,using the virtual excitation method and a program written in Matlab,the influence of vehicle speed,suspension parameters of the first series shock absorber and two-stage series ISD shock absorber on the power spectral density of each part of the vehicle system is calculated.The study founds that within a certain range vehicle speed has a positive correlation with the acceleration power spectral density of the vehicle body and the bogie.The second-stage suspension damping coefficient has a greater impact on the acceleration power spectral density of the vehicle body,the damping coefficient of primary shock absorbers has a great influence on the power spectral density of the bogie.The two-stage series ISD passive suspension has better performance in the low frequency band,and the ISD passive suspension has better performance in the high frequency band.Finally,the Sperling index is used as the evaluation standard for vehicle stability.The influence of different vehicle speed,suspension parameters of the first series shock absorber and two-stage series ISD shock absorber on the Sperling index is analyzed.The results show that the two-stage series ISD passive suspension system can effectively improve the vehicle’s smooth running.