A Theoretical Analysis Concerning the Influence of the Angle of Axes of Inertia on Vehicle Dynamics

The angle of vehicle principal axes of inertia is one of the basic properties of the vehicle. This paper presents the theoretical analysis concerning the influence of this property on vehicle dynamics.

First, we describe some preliminaries for analysis. Next, we calculate transfer functions from steer angle input to roll angle and yaw rate, so we understand that these transfer functions are influenced by the angle of principal axes of inertia. For example, when roll axis of inertia is forward and down, the gain of transfer functions from steering angle to roll angle and yaw rate and roll are respectively down in high frequency range (2-5Hz). Next, we make theoretical analysis of this phenomenon to this transfer function by two methods. One is the direct analysis of details of transfer function, and other is the analysis by separating transfer functions into two transfer functions making use of roll and yaw moment around center of gravity.

We investigate how the angle of the principal axes of inertia influences in each analysis. As a result, it is clarified that the numerator polynomial of the transfer function has a large influence in the first analysis. In second analysis, we clarify that the influence of transfer function from yaw and roll moment to yaw rate and roll angle is large.