Abstract:
Vehicles use suspension systems to attenuate vibrations for the purpose of ensuring
Ride Comfort and Road Holding which are contradicting requirements. The degree of
their contradiction can be minimized by optimization, employing an active suspension
system and using Coil Spring or Air Spring Suspension systems appropriately.
Theoretically, Air Spring Suspension systems are better than Coil Spring Suspension
systems on high vibration attenuation and less destruction to road. The objective of the
research is to compare the performance of Coil Spring Suspension with Air Spring
Suspension system through modelling and control of quarter car which is moving with
speed of 90 km/h on class-B road. The study gives a numerical figure on the
betterment of Air Spring Suspension system over Coil Spring Suspension system.
Mathematical model is developed for both systems and simulated in Simulink. The
mathematical models are validated with all the correlation coefficients are greater
than 0.48. The models are optimized using multi-objective Genetic Algorithm. The
optimized Air Spring Suspension system has better Ride Comfort and Road Holding
than Coil Spring Suspension system by 1.27% and 0.16% respectively. A Fuzzy Logic
Controller is developed and integrated to both systems to show their behaviour when
they are applied in active suspension system. The improvement of Ride Comfort in Air
Spring Suspension system is more than Coil Spring Suspension system by 3.73%. The
design of the air cylinder has to be good enough to prevent heat and pressure losses,
because the results of Air Spring Suspension system are obtained based on these
considerations.
