Modelling and model validation of an electropneumatic brake on subway trains

Abstract

In this paper, a model of the electropneumatic brake used on subway trains is developed; it facilitates brake system analysis, fault diagnosis and controller design. This objective is met by decomposing an electropneumatic brake into smaller modules and developing detailed models at three levels. The basic subcomponent models of the electropneumatic brake are built using a lumped parameter method. Then individual models are developed based on the subcomponent models. Finally, a complete model of the electropneumatic brake is developed by assembling all the valve models. Simulation models of these three levels are built using Matlab-Simulink. Important subcomponent models are verified by comparison with experimental results. Furthermore, a test rig is set-up to validate the complete brake model. Experimental and simulated results suggest that the model is able to closely predict the behaviour of the electropneumatic brake: brake filling and releasing time differences between experimental and simulated results are less than 10%; the cause of steady state pressure error of a real electropneumatic brake can be explained using the model; other behaviour of a real electropneumatic brake (sharp pressure jump and drop, pressure oscillation, thermal exchange) can be predicted and better understood using the proposed model.

Sliding mode pressure controller for an electropneumatic brake: Part II—parameter identification and controller tests

“…Details of measuring these parameters can be found in a paper published earlier. 2 Other plant and controller parameters are determined as follows.…”

“…Thermal exchange coefficients are determined indirectly by measuring the time constant of a pressure decay curve during pressure holding after quick air charging. 2,3 Some complicated parameters, for example, the correction coefficients in the air mass flow rate function, are determined iteratively by fitting the simulation results to the test data. Other parameters, for example, controller boundary layer thickness, are tuned during controller tests.…”

Sliding mode pressure controller for an electropneumatic brake: Part I—plant model and controller design

“…Complexity—electropneumatic brakes consist of many complicated valves that make the whole mathematical model very complicated; 1,2…”

A general method of braking process simulation for flexible marshalling EMUs

“…Modelling methods establish the mathematical model of braking systems based on the structure of components of the system, using theory of fluid mechanics, thermodynamics, etc. [1][2][3][4]. Identification methods usually place emphasis on the input and output of a system based on the test data and ignoring the internal mechanism [5][6][7][8].…”

“…Identification methods usually place emphasis on the input and output of a system based on the test data and ignoring the internal mechanism [5][6][7][8]. Luo et al [1] built a detailed model of an electropneumatic brake used on subway train by decomposing it into smaller modules at three levels. Pugi et al [2] proposed a simulation model library for a UIC pneumatic brake system, including elementary components such as pipes, orifices, valves and the reservoirs.…”