One of the various active suspensions, which have been shown to have considerable practical potential is the slow active scheme based on hydro-pneumatic components. However, previous studies of this system were restricted to using either a quarter or half vehicle model (two or four degrees of freedom). This paper is concerned with an analytical study of a multi-degree of freedom vehicle incorporating a passive and a slow active scheme based on hydro-pneumatic components. A full vehicle model of the hydro-pneumatic active suspension system is developed. This model includes the rigid body translation and rotational modes. This constitutes an extension of the state of the art, since previous investigations of hydro-pneumatic active suspension systems were restricted to bounce vibration control. The vibrations of the four-wheeled vehicle are induced by random road inputs at the left and right tracks. An investigation of the influence of hydro-pneumatic active suspension system on vehicle ride quality control is performed on this model and compared with the conventional passive suspension.The simulation results in the time domain showed that the hydro-pneumatic active suspension system is superior compared with the conventional passive one. Specifically, the root mean square of vehicle vertical acceleration is reduced by 29 % using hydro-pneumatic active suspension system |
