The sensitivity analysis of yaw rate for a front wheel steering vehicle: In the frequency domain

In this paper, the sensitivity analysis of yaw rate for a front wheel steering vehicle is performed in the frequency domain. A two degree of freedom system is used to represent a simple vehicle model in order to derive the system transfer function. The transfer function is defined between a steering angle input and a yaw rate output. This model shows the simplest lateral dynamic effect and is useful for understanding of the dynamic characteristics and control aspect of the target system. Vehicle mass, inertia, cornering stiffiness, and wheel base are selected as design variables. Sensitivity functions of the transfer function with repect to design variables are derived, and the results show that the response of the yaw rate always has stable minimum phase characteristics. The objective of this paper is the proposition of a base for re-design and new-design of the vehicle by checking the yaw rate variations with respect to the design variable change in the frequency domain. Finally, dominant design variables can be selected based on the sensitivity analysis.