An Active Vibration Isolation System for Vehicle Seats

The attenuation of vibrations transmitted from the road surface to vehicle occupants is an important issue for the minimization of discomfort levels which effect operator efficiency. Active vibration isolation strategies for automobiles have included active and passive suspension components which reduce the vibration levels of the sprung mass relative to the unsprung mass. However, an obstacle to the widespread deployment of these systems resides in the actuator's energy requirements to reduce the vibrations of the masses. To address the energy demand, research has been conducted on the attenuation of vibrations between the sprung mass and the seating system through a combination of passive and active isolation strategies. In this paper, a set of nonlinear models will be presented which describes the vehicle's passive suspension and seating system, and the occupant's vertical dynamics. A series of road disturbances and vehicle configurations have been considered in the simulations to establish vibration levels experienced by the occupant. These metrics serve as the design parameters for the design of an active vibration modulator which will be experimentally validated in the laboratory through emulation of the sprung mass' motion for the various road surfaces using a mechanical shaker. The modulator's design and active isolation system configurations will be discussed in terms of the tradeoffs between vibration attenuation and energy requirements.