Study On The Matching And Simulation Of Air Suspension Of The Commercial Vehicle

With the enhancement of our country economy status and improvement of people’s livingquality, people lay stress on performance of commercial trucks,heavy duty commercialvehicle is moving towards high power, light weight, high speed, safe, comfortabledirection.Nowadays,suspension of main commercial truck is leaf spring suspension, becauseof larger stiffness, higher frequency offset, overweighted quality, ride comfort of this form ofsuspension is neither ideal, nor in conformity with development of commercial vehicle.This paper mainly combines commercial truck positive development project in anautomobile design company, its structure is6x4, the elastic element suspension basically forconventional steel spring, we comprehensively improve commercial vehicle ride comfort sothat the suspension structure is improved, the front suspension structure of vehicle remainunchanged,the middle and rear suspension system needs improved, the leaf spring suspensionsystem is substituted for the air suspension system,finally,carry on the simulation analysis.（1）The matching of air suspension system. This paper describes the structure andperformance of air spring, analyzes the characteristics of different types of guiding structure,studies structure principle of valve selection,then matches the air spring and shock absorber,finally calculats the leaf spring stiffness the frequency offset and deflection of air suspension.（2）Design the fuzzy PID controller. Based on understanding the principles of heightcontrol valve structure, we do further study on its inflation and deflation,establish the dynamicequation and the state equation of the body and wheel two degrees of freedom.Build thesimulation model based on Simulink model,then combine the fuzzy control theory and PIDcontrol theory,then design the fuzzy PID controller. Conduct the ride comfort simulation testin the input of white noise road surface and different speed,compare the simulation results ofpassive suspension, PID control suspension and fuzzy PID control suspension system;（3）Build the vehicle model based on ADAMS/Car. At first, study on multi bodydynamics theory,establish the suspension, steering, tires,body,powertrain model according tovehicle technology parameters of the company,at last,finish assemblying the vehiclemodel,and generating random B and C level road.At different random road and vehiclespeed,conduct the ride comfort test,analysis the time domain and frequency domainsimulation results of the car body acceleration in the horizontal, vertical, vertical direction.The final summary: according to the calculation results of the suspension,the matching ofair suspension is reasonable;comparing to the passive suspension system and the PID controlsuspension system, fuzzy PID control can improve vehicle ride comfort; about the simulationresults of the vehicle model, the improved system can enhance the vehicle ride comfort.