The main causes for long-distance driving fatigue experienced by vehicle drivers are investigated
computationally using musculoskeletal modeling and simulation methods. A rigid-body model of
a prototypical adjustable car seat is constructed as a part of the present work and combined with
a public-domain musculoskeletal model of a seated human. Seated-human/car-seat interactions associated
with typical seating postures of the vehicle driver are analyzed using the inverse-dynamics
approach while the ‘‘minimum-fatigue’’ criterion is utilized to deal with the muscle redundancy problem
(i.e., with the problem that human-body contains more muscles than what would be typically needed to
drive various body joints).
The results obtained show that various seat adjustments (e.g., back-rest inclination, seat-pan horizontal
track position, etc.), driver’s back supports (e.g., presence/absence of lumbar support) and the
nature of seat upholstery (e.g., fabric vs. vinyl) can have complex influence on the muscle activation, joint
forces, soft-tissue contact normal and shear stresses, all of which not only affect the comfort perception
of the driver but also their feel of fatigue. Subsequently, the results of the present work along with
relevant public-domain literature findings (e.g., subjective driving-fatigue assessments provided by
human test subjects and human-body/seat contact-force measurements) are used to construct
a preliminary long-distance driving-fatigue function.
Relevance to industry: it is argued that the computer-aided engineering analysis introduced in the present
work should help speed-up the design of new high-comfort car seats. These seats are currently being
mainly designed using empiricism, legacy knowledge and extensive, time-consuming and costly prototyping
and experimental/field testing.