SEMI-ACTIVE SUSPENSION FOR A SEAT WITH A CONTROLLED ELECTROMAGNETIC DAMPER

Abstract

In vehicle suspension systems, the amplification of vibrations at resonance is considered the main problem. Secondary problems such as vibrations of wheel masses can be solved by conventional means like the 'three-mass configuration'. For the elimination of the main resonance, electronically controlled dampers must be applied. At the Delft University a new semi-active system with a rotational electromagnetic damper is developed. This system is studied theoretically and experimentally with deterministic and random excitations. The theoretical simulation model includes filtering of measured acceleration for obtaining the absolute velocity signal, the delay in the electromagnetic system and the locking through the frictional force. In a possible application for a sprung seat, the resonance can be eliminated. As result of non-linearities, some anomalies are encountered: subharmonic vibrations, medium-frequency disturbances and chaotic motions.