Abstract. Vibrations often interfere with driving comfort for riders and passengers. Variations
in loads, especially for four-wheeled vehicles, bumps, hollow road surfaces, and other forms of
road damage will greatly affect the vehicle suspension work system. This research aims to (1)
further test the effect of vertical dynamic load of the vehicle and change the dimension of
resistance on the road surface, (2) the contribution of spring and shock absorber to the load
fluctuation of the vehicle. Experimentally these load fluctuations are replaced by pneumatic
actuator forces of varying magnitude based on the regulatory pressure of the regulator. The
deviations generated by the varying load work are measured by placing a proximity sensor
along the spring movement. The vertical dynamic load transformation up to the road surface is
measured using a "Load cell" mounted under the wheels of the vehicle. Characteristics of
vertical dynamic vibration occurring due to several dimensional barriers, U (cm) obtained
using mathematical modeling method with 2 DOF suspension system transfer function. The
results showed a condition on the body and wheels of vehicles experienced a brief overshot for
0.14 seconds with deviation of 0.178 m. From the graph shows that the rate of deviation that
occurs is large enough that Y2d = 1.03 m / s caused by a sudden shock that occurred on the
wheels of the vehicle. This condition does not last long that is only duration t = 0.22 s, because
the contribution of springs and shock absorbers that can absorb vibration is 25% to the
vibrations caused by the vertical load of the body and the axis of the vehicle.
Keywords; Vibration, suspension, pneumatic actuator, deviation, vertical load