The natural frequency and damping ratio of the steering system are essential metrics for describing its dynamic characteristics. Since the driver rotates the steering wheel by applying torque, these metrics are critical for designing a more direct steering feel. They are obtained by solving a fourth-order characteristic equation. To achieve a compact representation, a three-step procedure has previously been proposed to derive approximate solutions. In this study, an alternative formulation is developed based on the known property that the natural frequencies are independent of vehicle speed. This property allows the derivation of eigenvalue formulas through purely algebraic operations. The resulting process is expected to facilitate clearer understanding and enable more precise application of the metrics in designing the dynamic behavior of steering systems.
Hideki Sakai (Fri,) studied this question.