Semi-Active Magnetorheological Helicopter Crew Seat Suspension for Vibration Isolation

A second-generation semi-active magnetorheological seat suspension (SAMSS) system was demonstrated in a helicopter crew seat for protecting the occupants from harmful whole-body vibration (WBV). MR dampers were designed, fabricated, and retrofitted into a tactical SH-60 Seahawk crew seat. These MR dampers are implemented in series with the existing fixed load energy absorbers (FLEAs) with minimal weight impact and in such a manner that the crashworthiness capability of the seat is not impaired. Additionally, integrated control electronics have been designed and integrated into the seat to provide real-time semi-active control, and performance is experimentally evaluated. Experimental test results have shown that this system reduced the dominant rotor-induced vertical vibration (4 per rev) transmitted to a 50th percentile male aviator by 89%, which is an 85% improvement over the original SH-60 crew seat. Furthermore, these experimental tests also show that this system significantly reduces vertically-induced seat rocking that occurs as a result of an offset center of gravity typical of crew seat designs.