抄録
Are there any indices to judge the degree of stability of vehicle in real time? The absence of the index can be one of reasons that vehicle dynamics is difficult to understand for common people. The absence of the index causes that reference models are currently used in many vehicle dynamics control systems in order to judge the states of stability in real time. However, there seems to be problems in the reference models regarding friction change of road surface unlike aircrafts. This paper challenges the above issue. Vehicle motion consists of the element of steering angle, front and rear slip angles. It is shown that the variable β_f-β_r which is taken element of steering angle out of yaw velocity is the effective index in expressing vehicle stability. A direct index which can be used for evaluating vehicles motion is found using a diagram of β_f-β_r and lateral acceleration. The index is valid in all condition including transient and non-liner state.
