Unkoo Lee
The Journal of Mechanical Science and Technology, vol. 23, no. 4, pp.889-893, 2009

Abstract : Current vehicle dynamic performance indices seem to be insufficient to represent the fundamental of vehicle dynamic performance because they are easily influenced by tuning elements such as springs. In this paper, suspension geometry is discussed as the basis of vehicle ride and handling performance. To analyze the characteristics of the suspension geometry, the screw theory is introduced. The screw axes surface, which is generated by continuous vehicle body motion, is the pure geometric property of the suspensions, and the shape of the surface is not influenced by tuning elements. Therefore, the shape of the screw axes surface can be regarded as the “genome” of vehicle performance. The gradients of screw parameters with respect to body lateral acceleration are proposed for new vehicle dynamic performance, and their correlation to vehicle performance is validated by full vehicle dynamic analysis.

Keyword : Vehicle dynamics; Screw theory; Screw axes surface; Vehicle dynamic performance index; Suspension geometry