Improving Control Mechanism of an Active Air-Suspension System

ABSTRACT: The technology of pneumatic vibration isolation for air-suspensions is developing gradually. As environmental vibroisolation requirements on precision equipment and air-suspensions become more stringent, the use of pneumatic isolators has become more popular, and their performance is subsequently required to be further improved. Due to air-suspension systems prevalence in heavy vehicles todays, improving control strategy and software base reformation can be an economical solution for performance improvement. In this study an active control technique, based on pressure is applied to a pneumatic isolator to enhance the isolation performance in the low frequency range where the passive techniques have difficulties. An air spring from air suspension system was modelled as the pneumatic isolator in a quarter-car model. The test plan for suspension model was in two approaches, model based simulation and experimental test, in order to evaluate the quarter-car suspension system. First, a mathematical model of an air-suspension for a quarter-car was built, in MATLAB-Simulink program. Then, the suspension prototype was prepared for the approach of experimental study. The experimental test design was based on physical equipment’s and performed in lab-view. Body acceleration, tire forces and suspension travel were outputs of experimental test. The optimization was investigated in two parts of dynamic performance including handling and comfort, and suspension travel as a structural performance. The results from experimental study were compared with simulative test from Simulink software in order to evaluate the percentage of simulation accuracy of active and passive approaches. The result comparison between active and passive suspension demonstrates 11.51% acceleration reduction during experimental test. Additionally, amplitude of suspension travel was reduced until 11.94% which shows structural improvement in vehicles suspension. Also dynamic forces were applied to the wheel, didn’t increase but also reduced until 3.04%. As conclusion, the new suspension performance was increased by applying control on system. Keywords: suspension, pneumatic, air-spring, control strategy, simulation and experimental tests. ……………………………………………………………………………………………………………………………………………………………………………………………………………………