A Study for Ride Quality Improvement Using Active Controlled Seat. Application of Frequency-Shaped Optimal Control.

One of the inherent limitations of active controlled suspension is the existence of an invariant point related to unsprung natural frequency. Aiming at the improvement of the ride quality at the invariant point, we focussed on a seat control equipped with an actuator between seat and body. From a functional point of view, the seat deflection must be small. Frequency-shaped functions are applied so that the seat control is effective at the frequency range, with small seat deflections at low frequency. As a result of dynamic simulations, it was clarified that the seat control is useful for vibration reduction at the desired frequency range and that integrated control of the suspension and the seat effectively improve ride quality.