Departmental Bulletin Paper 〈再録論文〉制駆動中の旋回限界特性についての基礎的考察

酒井, 英樹

The G-G diagram is one way of expressing the cornering limit during braking or driving. When limit driving data is plotted on a graph with the 2 axes representing longitudinal acceleration and lateral acceleration, the shape of the graph indicates the cornering limit. Although the theoretical outline with a one-wheel model is a circle, the shape on the braking side of a G-G diagram which uses actual measured data is similar to a pentagon. As a result, the basic shape of the diagram is unknown. Therefore this paper proposes a graphical method which uses a two-wheel model to explicitly describe the mechanism that determines the G-G diagram shape. This graphical method is as follows. First, the provisional cornering limit line for the front wheel is plotted in the G-G diagram, ignoring the rear wheel cornering limit. Second, the provisional rear wheel cornering limit is plotted in the G-G diagram, ignoring the front wheel cornering limit. Third, the lower of the two cornering limit lines becomes the shape of the G-G diagram. The reason that the braking-side shape of actual measured data looks like a pentagon is due to the fact that these lines cross each other at two points. Furthermore, this paper describes the vehicle behavior when the diagram shape is the front wheel cornering limit line as "plow", and the behavior when the shape is the rear wheel line as "spin". Finally, this paper explains that the cornering limit increases in the order of rear-engine rear-wheel drive (RR), front-engine rear-wheel drive (FR), and front-engine front-wheel drive (FF) vehicles due to the effects of the engine position and position of the drive wheels.

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