Study on modelling and control methods of air spring in railway vehicles

An auxiliary space is set up between the connecting pipe and orifice to solve the linkage problems in the previous non-linear models of air spring. A new non-linear model of air spring called TPL-ASN model including the sub models of various components is established based on the theories of aerodynamics, fluid mechanics and engineering thermodynamics, and etc. The dynamic characteristics of a high-speed EMU air spring are calculated by the self-designed Air Spring Dynamic Characteristics Simulation Software (ASDS software for short) based on the TPL-ASN model. By comparisons with the test results and simulation results, it shows that the TPL-ASN non-linear model can accurately simulate the non-linear characteristics of air spring, which can well reflect the amplitude characteristics and frequency characteristics. A new force element called TPL-ASN-COUPLE is developed in the multibody software SIMPACK based on the TPL-ASN model. Two multibody dynamic models coupled with a two-point suspension system and a four-point suspension system are established respectively using the TPL-ASN-COUPLE force element. Simulation results show that various control methods have great influences on vehicle performances and they should be considered in the air spring system modelling. Besides, the valves should not be ignored in the process of air spring modelling.