Abstract: The matching between damping and spring stiffness of the electronically controlled air suspension with stepped adjustable damping under different working conditions is presented. The stiffness characteristic of air spring is analyzed and the curve between the height and effective area is fitted with polynomials. Considering the nonlinearity of the air spring, two-mass nonlinear dynamic model is established. The improvement of ride comfort is taken as the target, and the suspension working space and dynamic load are taken as constraint conditions. The genetic algorithm is adopted, and the influence of road surface, vehicle speed and on-spring mass on damping is analyzed. Then optimization strategy for damping is designed and the control method of three stepped adjustable damping is determined according to optimization. By establishing the nonlinear dynamic system model of half-vehicle, the validity of the control method of three stepped adjustable damping is investagted. Finally, the result of analysis indicates that the ride comfort can be improved effectively through matching between damping coefficient and spring stiffness under different working conditions.

Key words: Genetic algorithm, Ride comfort, RMS, Suspension optimization