Modelling of all-wheel drive motorcycle for dynamics analysis and control

Over the years, the trend of innovation and development of all-wheel drive (AWD) solutions for motorcycles has undergone a great delay compared to what occurred for cars, although four wheeled drive systems have shown to bring undoubted advantages in terms of safety, as well as in terms of stability and handling of the vehicle. The factors contributing to this delay are manifold. Jointly with market shares motivations, the most intuitive reason concerns the mechanical difficulties in distributing the torque to the front wheel, not to mention the complexity in managing the nature inherently unstable and highly nonlinear of an under actuated two-wheeled vehicle. The few commercial proposals available on the market, exploit only partially the potential of an AWD motorcycle, indeed, they are conceived to transfer to the front wheel only the exceeding part of the drive torque during the rear wheel slip. In this work, an AWD motorcycle model with attached rider is proposed. It has been developed a dynamic model in a symbolic way, and then compared with a multi-body simulation software. It allows investigating the front wheel drive effects on the motorcycle dynamics. The proposed model takes into account the lateral dynamics, the longitudinal dynamics and the tyre-road interactions