Quadratic Performance Indices and Optimum Suspension Design

This paper presents some results obtained from the computer simulation of a two-dimensional linear vehicle model with coupled bounce and pitch modes. The effects of variations in the ratio of front to rear spring stiffnesses and the inertia coupling ratio on various performance indices for ride quality and road holding were investigated. Two forms of input to the system were considered, ( a) isolated smooth bumps of varying length and ( b) continuous random type excitations. Allowance was made for the time delay between the inputs at the front and rear wheels due to the forward speed of the vehicle.