Object oriented modeling and simulation of a pneumatic brake system with ABS

A new modeling and simulation methodology for a pneumatic brake system with ABS widely used in commercial vehicle is presented. The main parts of the pneumatic brake system such as air storage reservoir, tandem dual circuit brake valve, relay valve, ABS air regulating valve and diaphragm brake chamber are included and modeled by an object oriented implementation of the multi-domain unified modeling language Modelica so that the characteristics of multi-domain interactions can be considered. All the modeling and simulation processes are realized by a Modelica language based software-MWoks. The delay time of gas pressure in pipelines is also considered in the model. The dynamic responses of each part and the coupling characteristics for brake pedal force, pedal travel and the output force of brake chamber are both obtained. Finally, the simulation results are validated by experiments.