Active Control of Uncertain Seat Suspension System Based on a State and Disturbance Observer

In this paper, an active seat suspension system that is robust to uncertainties and unknown road profiles is designed using a state and disturbance observer. The controller which needs the measurement of just the seat frame position is analyzed with a 4-degree-of-freedom biodynamic model of the passenger for performance and stability. The proposed scheme is validated by simulation for a variety of road profiles under various uncertainties and compared with passive suspension, linear quadratic regulator-based active seat suspension, and conventional active cabin suspension using the evaluation norms set by ISO-2631. The proposed scheme is seen to be robust to uncertainties in seat frame suspension, passenger mass, and cabin suspension.