Ride Simulation of Passive, Active, and Semi-Active Seat Suspensions for Off-Road Vehicles

147 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.Mathematical models were developed for passive, active, and semi-active suspension systems for off-road vehicle seat suspensions. Each suspension model was combined with a three degree of freedom model of the vehicle operator to formulate models of the ride systems of off-road vehicles. Ride performance of the suspension systems were computer simulated using the ride models at the various natural frequencies and damping ratios of their suspension systems.The input vibrations for simulation of the ride models were obtained by measuring a real time history of acceleration data at the base of the seat suspension of agricultural tractors during the transport and moldboard plowing operations. The output vibrations from the model simulation were presented in terms of the ISO frequency weighted root mean square accelerations of the operator's head, body, and pelvis at the preferred third octave frequency bands. The acceleration levels were evaluated in the criteria of the ISO 8 hour fatigue-decreased proficiency boundary. Absorbed power of the operator was also computed for assessing relative ride performance of the suspension systems.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD