Modelling and simulation of locomotive driver's seat vertical suspension vibration isolation system

The paper describes the simulation of a vertical seat suspension system with a variable damper. The model presented describes a real damper with bushings and is an extension of the classical linear SDOF oscillatory system. Transfer functions were identified from laboratory measurements and the mechano-mathematical model produced was validated by field measurements. The seat cushion parameters were identified from laboratory measurements and combined with standardized vertical (z-axis) seated human body models (ISO 5982 and DIN 45676). These models, together with an inert mass human body model, were used to predict the vibration mitigation performance of the seat-occupant system. The results were compared to data obtained from field measurements under real operating conditions. It was found that the use of the inert mass human body model resulted in the smallest differences between predicted and measured system vibration isolation performance for the field excitation in the frequency band up to 4.5 Hz, where most of the vibratory energy was present in the field. Hence this simplified model is suggested for prediction of vibration influence on locomotive driver under field conditions.