The Development Of Electronically Controlled Air Suspension Control Strategy And Test Bench

As the automobile technology developed, not only vehicle’s stable maneuverability waspursued but also its ride comfort was required; The enhanced stiffness was required to ensurevehicle’s stable maneuverability at high speed, however, the reduced stiffness was required toobtain the soft riding at uneven pavement for a long time; But the conventional suspensioncannot meet these requirements for its stationary stiffness, however, the air suspension equippedgood stable maneuverability and soft riding for its variable stiffness. ECAS can keep the vehicleat the standard height, thus the suspension’s stationary frequency was ensured and vehicle’sstable maneuverability was improved; Vehicle height can be lowered so as to reduce windresistance and improve soft riding, So ECAS was widely applied to bus and truck; The airsuspension’ characteristic and control strategy was deep researched by this article for this topic.First of all, this paper tested the air spring’s characteristic and matched the characteristiccurve of three kinds of air spring’s primary status by building air suspension test bench; Themathematic model of air spring’s stiffness and frequency was established, and then the factorinfluencing air spring’s stiffness and frequency was investigated by this paper; The air spring’smathematical relationship between height and frequency was found by mathematical derivationwhich can support the theoretical basis for air suspension match.Secondly, three heights of ECAS were introduced in this paper. Based on the Simulinksoftware tool, the control strategy of air suspension on rear axle only was developed, whichincludes start module, manual module and dynamic regulation module, and then the heightdeviation control module was introduced in the paper and simulated by the inflation anddischarge model of air spring, the result of simulation showed that the control strategy of heightdeviation control module was completely correct.Finally, a controller was designed according to the height sensor and solenoid valve ofECAS; The analog signal detection circuit, solenoid valve drive circuit and SCI communicationcircuit were introduced in this paper. The PC software developed by GUI module of MATLABcan satisfy the function of detection, manipulation, and parameter calibration.