According to the designs of the PA, it can be seen that it is
in fact two-dimensional-search problems by tuning two
parameters of interest, ωn and ζ . The searching problems can
be globalised by varying these parameters throughout the range
of values of practical significance. This resulted in 150 simulation
runs for each case. The random road input model [13] was used
to excite the systems. The three vehicle response variables of
interest ( b &
z& , w b z − z , r w z − z ) were monitored and averaged by
the root mean square (rms) method. The rms w b z − z , r w z − z
were presented in the percentages of each maximum range [13].
The results of the global searching are in the form of carpet plots
of b &
z& vs. w b z − z and b &
z& vs. r w z − z respectively. Therefore, a
comparison between the global investigation for the passive and
active suspensions can be made.