Study On System Of Electronically Controlled Air Suspention For Passenger Car

Suspension is one of an important part for vehicles.It links the bridge and body flexibilitily,and buffers multi-driving forces that the vehicle encountered when steering.Electronically controlled air suspension system (ECAS) is a more advanced suspension system at present,which get more and more used widely with good damping properties in vehicle's vibration control.Compared with foreign countries, the development of electronic control air suspension system in our country is still in its infancy,therefore,to study and develop the air suspension system has an important significance.In this paper,analysised the important parts of air suspension-air spring in-depth,and had a test to validate its nonlinear characteristic.Based on understanding the principle and compositions of electronically controlled air suspension system,combined with the actual situation and the subject of Yaxing YBL6891H passenger car's specific parameters,expounded the height sensor detection circuit principle and installation,electromagnetic driving circuit principle and installation.The control system was installed on vehicle to have a calibration test,mainly described how to use the calibration software.A reasonable control strategy is important for improving the performance of electronically controlled air suspension system.In the paper,for the tested passenger car,the neural network algorithm was selected in suspension system because of its self-organization and self-learning, through adjusted the body height to changes stiffness of air spring to achieve damping. In Matlab+Simulink software environment,established a quarter vehicle suspension model and had a simulation analysis,vehicle body vertical vibration acceleration,wheel loading and suspension dynamic stroke these three evaluation indexs as the object of investigation.The simulation results show that the neural PID controll algorithm can improve vehicle ride comfort and stability and has obvious advantages compared with the leaf spring.Electronically controlled unit was installed on the modified Yaxing YBL6891H passenger car for validating its performance.In A,B,C three levels road had a ride experiment,the content of experiment consisted of the body vertical acceleration and highf sensor output signal.With the body vertical acceleration to calculate the one third frequency doubling acceleration root mean square (RMS) value and map the spectrum.According to the obtained experimental results,we can see that the air suspension of performance can meet the requriment which was ruled in the QC / T 474-1999 "Passenger car Ride evaluation " ,and at the same time,it can meet the project's requirements.