Sensitivity analysis of side slip angle for a front wheel steering vehicle: a frequency domain approach

In this paper, sensitivity analysis of side slip angle for a front wheel steering vehicle is performed in the frequency domain. For the derivation of the transfer function, a simple vehicle model with two degrees of freedom is used in the initial modeling stage. This model exhibits the simplest lateral dynamic effect, and is useful for understanding the dynamic characteristics and control aspects of the target system. Vehicle mass, inertia, cornering stiffness, and wheel base are taken to be the design variables. Sensitivity functions of the transfer function with respect to the design variables are derived. From this study, we see that a transition speed exists in the frequency response of side slip angle. This implies that the characteristics are changed from minimum phase to non-minimum phase as the vehicle speed increases. The objective of this study is to propose a basis for design and re-design of the vehicle by checking the side slip angle variations with respect to design variable changes in the frequency domain. Finally, dominant design variables are suggested based on the sensitivity analysis.