OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
The labels used for linguistic variables are mentioned as: NL (Negative Large), NM (Negative Medium), NS
(Negative Small), ZE (Zero), PS (Positive Small), PM (Positive Medium) and PL (Positive Large). Implemented
fuzzy control rules are presented in Fig. 8 to achieve maximum passenger ride comfort including driving safety
and vehicle handling.
Fig. 8: Fuzzy Logic control rules
Fig. 9: Fuzzy membership functions
5. Simulation Work
Practically, road surface profile is uneven i.e. varies from place to place having bumps and holes. When a vehicle
passes through such type of roads, the excitation input generates vibrations in the whole vehicle body.
Effectiveness and proper choice of controller system depends upon suspension system behavior on the input
parameters of a real road condition. In present case, vehicle suspension effectiveness is studied by considering
the simple functions such as step function, sine wave function, cosine wave function and random excitations for
simulation purpose as the input disturbances from the road surface. In every case the vehicle forward velocity is
assumed to be constant.
Case 1: Step Input
In second case, the step input excites the dynamics of the quarter car suspension model as the vehicle hitting it on
the real road conditions like bump input. The amplitude for the present step input case is having initial value of
zero and a final value of 10 cm.
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