Model identification of a car suspension testbed for robust vibration control

Road irregularities are a source of structure-borne noise in a car cabin. An active suspension using an Hinfinity robust feedback controller is designed to reduce this vibration-induced noise. To define the control law on this suspension, a quarter-car suspension is first modeled through its resonance modes. Frequency responses are extracted from experimental measurements which are then curve-fitted to obtain the nominal model of the suspension and its parametric uncertainty. The vibration-induced noise in the frequency range 60-250 Hz is then reduced using robust feedback controllers. An Hinfinity controller and two mu-synthesis controllers are designed and compared. Simulation of these controllers using Simulink result in a reduction in vibration at resonance peaks of up to 31 dB.