Optimization of Suspension System to Minimize Tire Dynamic Force

Suspension system has to perform complexity requirements, which includes road holding and equality, driving pleasure, riding comfort to occupant. Riding pleasure depends on vertical acceleration, with main objective to minimize vertical acceleration. The force transmitted by the deflection of tires to the unsprung mass is known as the Tire-Dynamic Force (TDF). The force should be considered while designing the suspension system. The TDF can cause vehicle instability and increase in the sprung mass acceleration. The objective of this research work is to minimize the TDF by optimum suspension design so that minimum vertical accelerations would be experienced by the passengers. To minimize the vertical acceleration, mathematical model of 2-DOF Quarter car model is considered for passive suspension system. Its equation of motion is formed with correlating objective function. Thus having objective function to, minimum weighted root mean square accelerations as per ISO 2631, viz. formulated for optimization. spring stiffness and damping coefficient are used as variables during optimization. The Genetic Algorithm is implemented as optimization tool with above mentioned objective function. The optimization results obtained were simulated and are compared with classical values. It is observed that the Seat acceleration, using optimized values, is reduced by 8.76% compared to the classical values. From experimental validation main objective function of Tire dynamic force value reduced from 2300 N to 2100 N, it is decreased by 8.69 % and Seat acceleration reduced from 34.9176 m/s2 to 32.0121 m/s2 after replacing the conventional by optimized strut. Thus provides improved ride comfort to occupant/driver.