  Head motion is a key determinant of motion comfort and differs substantially
from seat motion due to seat and body compliance and dynamic postural
stabilization. This paper compares different human body model fidelities to
transmit seat accelerations to the head for the assessment of motion comfort
through simulations. Six-degree of freedom dynamics were analyzed using
frequency response functions derived from an advanced human model (AHM), a
computationally efficient human model (EHM) and experimental studies.
Simulations of dynamic driving show that human models strongly affected the
predicted ride comfort (increased up to a factor 3). Furthermore, they modestly
affected sickness using the available filters from the literature and ISO-2631
(increased up to 30%), but more strongly affected sickness predicted by the
subjective vertical conflict (SVC) model (increased up to 70%).
