Box's method is used to determine the elastic and damping characteristics of a vehicle suspension that optimize the ride properties of a car. A seven degrees of freedom vehicle model is used. By this method, it is possible to consider springs and dampers with non-linear characteristics. An objective function that takes into consideration vertical and rotational accelerations of the vehicle was used, permitting the optimization of ride characteristics. Also, by adding a term in the objective function related to the dynamic tyre load variation, we can simultaneously optimize the handling behaviour of the vehicle. Moreover, constraints were used in order to limit all theimportant design parameters of the problem (the suspension working space, the elastic characteristics of the springs and damping characteristics of the dampers) to acceptable values from the engineering point of view. The method is illustrated by a numerical example. (A).
Abstract