Wheelbase filtering effect on vehicle ride dynamics

The time delay of rear wheel input relative to front one acts to filter the amplitude of vehicle motion. Through reference to a half-car pitch plane model, mechanism of wheelbase filtering was investigated. Amplitude of FRF between a motion and road input could be divided into two parts: steady part and variable part. Steady part that is determined by natural property of vehicle does not change with outer input condition. However, variable part fluctuates frequently because of cosine function item of itself, which is closely related to velocity of vehicle. It is variable part that modulates the amplitude of vehicle motion. In addition, wheelbase filtering effect varies greatly at different locations on the body. Filtering effect on work space and dynamic tire load of suspension was also studied. Results show that rear road input hardly influences front suspension motion and vice versa, so variable part is much smaller than steady part and filtering effect in suspension motion is not obvious.