Abstract
This research will compare the transient response
characteristics of a four-degree-of-freedom, roll-plane
model, representing a class 8 truck, using passive and
semiactive dampers. The semiactive damper control policies
that are examined include the previously developed policies
of on-off skyhook, continuous skyhook, and on-off
groundhook control, along with a newly developed method of
fuzzy logic semiactive control. The model input will
include body forces and torques, as well as transient
displacements at the tires. The model outputs include the
vehicle body heave and roll displacements, the vertical
displacement of the tire (wheel hop) and the vertical
acceleration of the vehicle body. For each output, the
maximum peak-to-peak and RMS values of the response are
examined.
The results of the study show that semiactive dampers have
minimal effect on improving the vehicle body and tire
transients due to forces or torques applied to the body, as
compared to passive dampers. For road inputs, however,
semiactive dampers are able to provide a more favorable
compromise between the body and axle transient dynamics,
when compared to passive dampers. The fuzzy logic
semiactive control policy that is proposed in this research
is better able to balance the body and axle dynamics than
the conventional semiactive damping control policies that
are investigated. Further research on the application of
fuzzy logic semiactive control concepts is suggested, in
order to fully investigate the potential of such control
schemes for vehicle suspensions.
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