SAE International Investigation of the Behavior of Three-Wheel Vehicles When They Pass Over a Low \u03bc Road Surface 2016-32-0051

In recent years three-wheel camber vehicles, with two wheels in the front and a single rear wheel, have been growing in popularity. We call this kind of vehicle A "Leaning Multi Wheel category Vehicle" (hereinafter referred to as a "LMWV"). A LMWV has various characteristics, but one of them stands out in particular. When a LMWV is cornering, if one of the front wheels passes over a section of road surface with a low friction coefficient, there is very little disturbance to the vehicle's behavior and can continue to be driven as normal. However, there has been no investigation into why these vehicles have this particular characteristic. Consequently, in this paper an investigation was carried out in order to determine the behavior of a LMWV in this situation. First, measurements were taken using an actual vehicle to confirm the situation described above. As a result, it was confirmed that there is only a small change in the vehicle's posture and also that the other front tire generates tire force that appears to compensate for the decrease in lateral force. Next, a multibody dynamics analysis was carried out. The results of this simulation indicated that the cause of this phenomenon is the steering turns toward the inside of the corner and the other front tire develops a slip angle which in turn generates a lateral force. The investigation and analysis described above clarified this phenomenon and demonstrated one of the factors that gives a LMWV its cornering stability.