Limit of cornering of motorcycle

Abstract

In the case of four-wheeled vehicles, as a method to indicate the cornering limit performance, the G-G diagram is used. In a G-G diagram the longitudinal acceleration and lateral acceleration of the vehicle are set as the two axes. A visible outline of the data when the vehicle is being driven at the limit is drawn on these axes to show the height of the cornering limit. Further, another type of G-G diagram that also indicates which of the front or rear wheels have reached their limit has been proposed. Since the height of the cornering limit, as well as which of the wheels has reached the limit at that time will all be discussed for the cornering limit performance of the motorcycle, it was determined that this G-G diagram should also be suitable for studying motorcycles. However, this G-G diagram cannot be applied to motorcycles as is. This is because the yaw moment balance conditions are different for motorcycles and four-wheeled vehicles. During the cornering of a four-wheeled vehicle, there are two yaw moments acting around the center of gravity of the vehicle due to the cornering force of the front wheels and the rear wheels. However, during the cornering of a motorcycle, there is another yaw moment that acts on the vehicle in addition to these two yaw moments. This third yaw moment is due to a braking and driving force. Therefore, in this paper, the three moments acting on the motorcycle will be converted into the two moments that act on a four-wheeled vehicle so that this G-G diagram can be applied to motorcycles. Further, the front wheel braking force distribution ratio that would produce the maximum height of the cornering limit was studied to propose a criterion assuming combined brake system (CBS) control during cornering.