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Motorcycle dynamics in braking and curves: The effect of the rider technique and road condition

The study of motorcycles presents an interesting example of teaching that combines theory, technology and application. In this paper, we present a typical dynamic study conducted in the discipline of Motorcycle Engineering, UFPE. The problem is to determine when a motorcycle should begin its breaking and what would be the maximum speed to make a curve. To study this phenomenon, we model the dynamics of the motorcycle on straight and curved paths, considering the inertial forces, resistive forces and the forces controlled by the rider (propulsion and braking). The models are then used to study the minimum distance to start the braking and the maximum possible cornering speed, considering the limits of adhesion and the possibility of loss of contact of one of the wheels. As result, we conclude, from a safety point of view, that it is important to consider the resistive forces on the model of maximum cornering speed, but not in the calculation of the minimum braking distance. Another important result is that the optimum braking technique (ratio of front and rear braking) is a function of the friction coefficient, so it is not interesting to recommend to the riders a universal proportion.

Keywords:
motorcycle; braking; curve dynamics


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