Control over negative effects of vertical vibration on independent steering/driving wheels of an electric vehicle

On basis of the structure features owned by the suspension system under the four-wheel independent steering and driving electric car (FWISDEV) designed, the passive suspension model and active suspension model are established. Research shows that: the increasing un-sprung mass has little effect on both of the suspension working space (SWS) and body acceleration(BA), but exert a tremendous influence on the wheel relative dynamic load (WRDL); a reasonable selection of suspension rigidity and damping ratio may better relieve the effects of increasing un-sprung mass on WRDL. The Stochastic Linear-Quadratic Optimal Control-based active suspension, compared with passive suspension designed, may significantly reduce RMS values of WRDL and BA and take into account both of the stability and ride comfort, the performance of which will reach even exceed that as the traditional vehicles show; furthermore, compared with other suspension, active suspension has SWS though enlarged, still within the reasonable designed scope.