SAE Update - December 2022 - 14

TECH FOCUS:
VEHiClE DyNAMiCS
The transcendent role
of vehicle dynamics
A Ford Focus research vehicle owned by Kettering University and used for
ride comfort testing with a cleat transient input, which is a pine crown
molding attached to the road surface with duct tape.
what are called " combined slip "
maneuvers. You can think of
these maneuvers as harsh
driving scenarios that usually
happen on real roads during
accident avoidance, when a
driver is both braking and
steering to prevent a collision.
My student is working on an
analytical, closed-form
mathematical model of a
conventional vehicle (that is
being converted to an
autonomous vehicle), which is a
fancy way of saying that he is
writing the equations of vehicle
motion himself. The idea is to
have enough fidelity to the
" ground truth " to represent
vehicle behavior in a broad range
of vehicle maneuvers, but still
14
December 2022
Vehicle responses measured inside a Ford
Focus research vehicle when the left track was
subjected to a cleat transient input. The top
subplot shows vertical acceleration as
measured at the driver's seat track. The
bottom subplot shows sound pressure as
measured at the driver's right ear. it is
challenging to relate these measurements to
human perceptions of the vehicle
environment.
have a mathematically small enough model to require
minimal compute resources to solve. The vehicle
model is being developed in MATLAB and Simulink
software, and validation of this model is a big part of
the project.
2. Investigation of the relationship between
measured vehicle responses and human perception of
vibration. In this research project, I am investigating
vehicle vibration quality and ride comfort with
transient inputs. The vehicles in the study are driven
in a straight line over a cleat, which is the source of
vibration excitation. The goal of the project is to
relate human perception of vibration quality to vehicle
responses measured inside of the vehicle. My previous
work with steady-state vibration has shown that
human perception of vibration can be compared to
how humans perceive sound, where both the
amplitude and the frequency of the excitation will
alter its perception. Thus, a simple measurement of
vibration overall level is insufficient to predict comfort.
The study involves measuring vehicle vibration
UPDATE
Kettering University
SAE Update - December 2022

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