Evaluation of Frequency Response Characteristics on “g-g” Planes by Using Quasi-steady State Analysis

This study investigates a methodology to visualize the representative motion characteristics with consideration of running conditions, as well as the quantitative effects of the fundamental specifications for the vehicle dynamics. Frequency response is a method of evaluating the dynamic characteristics of a vehicle by examining the vehicle-motion response to steering input. Additionally, the proposed methodology considers running conditions which are represented by longitudinal and lateral accelerations, the response characteristics are visualized on “g-g” planes. Quasi-steady state cornering is assumed so as to calculate the characteristics with consideration of horizontal acceleration. Moreover, sensitivity is defined to evaluate the quantitative effect of a design parameter on a characteristic value which is the gain or phase of the frequency response, and the design parameters indicate the vehicle fundamental specifications in this study. It is also possible to visualize the sensitivities on “g-g” planes. The proposed methodology indicates relationships between the characteristics and the design parameters of a vehicle. This contributes to exploring a good design solution efficiently without many design iterations.