Analysis of the stability of motorcycles during braking maneuvers

The decreasing number of road accidents in Europe is correlated to the massive application of active safety systems on the vehicles. The evolution of advanced safety technologies, unfortunately does not apply also to Powered Two-Wheelers (PTWs). The raising trend of PTWs circulation in the streets has not been followed by an equal development of innovative active safety systems for those vehicles. The complex dynamics of PTWs slows down the design of new technologies and limits the possibility to find relevant solutions to address crucial aspects for road safety, as the vehicle stability under emergency situations. That points out the necessity to develop new advanced riding assistance systems able to enhance the riders and PTWs safety. Accordingly, the present work studies the potentialities of the current braking systems for PTWs application and describes the design of a new braking system. Relevant issues related to the development of the advanced braking system, as the real-time estimation of the vehicle speed and tire-road friction, are addressed. Fall detection parameters, used to control the stability of the vehicle during emergency maneuvers, are defined and verified by virtual and experimental data. The analysis of different aspects correlated to the braking dynamics of PTWs gave the possibility to define a new concept of braking force modulation applicable in case of loss of stability. Rationales, benefits and limitations of this new safety function, named Active Braking Control (ABC), are presented in detail. The virtual tests carried out to assess the potentialities of the system, demonstrated the effectiveness of the new braking force modulation strategy, in terms of improvement of vehicle stability and control.