Optimal suspension performance for 2-D vehicle models

Abstract

A study is described which was a comprehensive investigation of potential benefits of preview control applied to a linear, two-dimensional (2-D), four-degree-of-freedom, half-car model. The model includes vehicle sprung mass pitch and heave dynamics, and front and rear unsprung masses. By using the discrete-time, optimal Linear Quadratic (LQ) control formulation, it is shown that the preview based on front wheel inputs can contribute to up to 70% reduction of vehicle r.m.s. acceleration, for a given suspension travel, and up to 50% reduction in tire deflection, for a given acceleration level. These improvements are in addition to those already achieved with active suspensions without the preview. The results also indicate that, in view of the available preview times, the preview control is most beneficial at higher speeds and rougher roads.