Comparative Study of Coil Spring and Air Spring Suspension system on Quarter Car Model

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.