Influence of biomechanical compliance on control performance of a magnetorheological sliding seat system

We investigate the feasibility of a sliding seat with a magnetorheological (MR) energy absorber (MREA) to minimize loads transmitted to a payload in a ground vehicle for frontal impact speeds ranging as high as 7 m/s (15.7 mph). The crash pulse for a given impact speed was assumed to be a rectangular deceleration pulse having a prescribed magnitude and duration. The control objective is to bring the seat system to rest using the available stroke, while accommodating changes in impact velocity and occupant mass ranging from a 5th percentile female to a 95th percentile male. The seat system was first treated as a single-degree-of-freedom (SDOF) rigid occupant (RO) model, and two control algorithms are developed: (1) constant Bingham number control and (2) constant force control. To explore the effects of occupant compliance on the adaptive seat system performance, a multi-degree-of-freedom (MDOF) compliant occupant (CO) model was integrated with the seat mass and the same control algorithms were used. Simulation results showed that the designed adaptive controllers successfully controlled load-stroke profiles to bring the seat system to rest in the available stroke and reduced occupant decelerations. Analysis showed extensive coupling between the seat structures and occupant biodynamic response.