Semi-Active Damped Seating Technology for the EFV

The Expeditionary Fighting Vehicle (EFV) is an amphibious vehicle designed to operate through harsh conditions and at much higher speeds than its predecessors. These capabilities and broadly vary operational conditions lead to a complex design and human factors scenario for the forward seating positions that cannot be solved using a passive seat suspension. Injurious shock loads transmitted to the occupants when traversing over water in high sea states as well as harmful shock and vibration transmitted to the occupants when the vehicle is traveling over land pose a threat to occupant health and significantly limit mission length. To address this, a retrofit-capable Semi-Active Magnetorheological Vehicle Seat (SAMVS) system was developed in Phase I which adapts to these broadly varying operational conditions as well as occupant weight to provide optimal protection of the occupant during EFV missions. The key technologies behind the SAMVS system is a retrofit-capable magnetorheological (MR) damper that can be electronically controlled by compact control electronics featuring a control algorithm developed specifically for this application. With these technologies, the SAMVS system enables a unique single solution for all shock and vibration environments encountered by the EFV. It has been shown that the SAMVS system can reduce the shock dosages applied to the occupant by 33% in water mode and reduce the vibration transmitted to the occupant by 65% as compared to the current passive suspension system. Further performance gains are expected in Phase II as a tactical prototype system is fabricated, tested, and refined.