Research On The Control System Of Electronically Controlled Air Suspension

Taking the Electronically Controlled Air Suspension(ECAS) as the research object, the paper discusses the building-up of its control system based on cosimulation between MATLAB/Simulink and ADAMS/Car using Neural Network and fuzzy theory. Then cosimulation is used again to validate the correctness of the control system.Firstly, the whole vehicle air suspension system is built up based on ADAMS/Car. Considering the vehicles of the same type in foreign countries a double wishbone front suspension and multilink rear suspension are adopted to form a full vehicle, then the suspensions'kinematic parameters are optimized. After that some other subsystems such as car body, steering, powertrain, breaking and tires subsystems are selected.Secondly, the software part of the ECAS is designed including vehicle height control subsystem and car body pitch control subsystem. For the height control part, two air springs of front suspension are controlled separately and two rear suspension are controlled together. For each single controller the gas charge and exhaust processes are considered too. A PID height controller is built up first, then a BP Neural Network height controller is built up. After comparing two height controllers'performance a hybrid height controller is built up lastly. For the car body pitch controller there are three controllers too. According to the vehicle running data which can be easily obtained a fuzzy body pitch controller is built up.The simulation results either from separate ones or from vehicle ride and stability simulations according to our national standards show that, the designed full vehicle air suspension is reasonable; the performance of designed air suspension controller is excellent and can be put into application.