Development of kineto-dynamic quarter-car model for synthesis of a double wishbone suspension
Abstract:Linear or nonlinear 2-degrees of freedom (DOF) quarter-car models have been widely used to study the conflicting dynamic performances of a vehicle suspension such as ride quality, road holding and rattle space requirements. Such models, however, cannot account for contributions due to suspension kinematics. Considering the proven simplicity and effectiveness of a quarter-car model for such analyses, this article presents the formulation of a comprehensive kineto-dynamic quarter-car model to study the kinematic and dynamic properties of a linkage suspension, and influences of linkage geometry on selected performance measures. An in-plane 2-DOF model was formulated incorporating the kinematics of a double wishbone suspension comprising an upper control arm, a lower control arm and a strut mounted on the lower control arm. The equivalent suspension and damping rates of the suspension model are analytically derived that could be employed in a conventional quarter-car model. The dynamic responses of the proposed model were evaluated under harmonic and bump/pothole excitations, idealised by positive/negative rounded pulse displacement and compared with those of the linear quarter-car model to illustrate the contributions due to suspension kinematics. The kineto-dynamic model revealed considerable variations in the wheel and damping rates, camber and wheel-track. Owing to the asymmetric kinematic behaviour of the suspension system, the dynamic responses of the kineto-dynamic model were observed to be considerably asymmetric about the equilibrium. The proposed kineto-dynamic model was subsequently applied to study the influences of links geometry in an attempt to seek reduced suspension lateral packaging space without compromising the kinematic and dynamic performances.
Document Type: Research Article
Affiliations: CONCAVE Research Centre, Concordia University, Montreal, QC, Canada
Publication date: January 1, 2011