Assessing Tire Performance from Vehicle Dynamic Transfer Functions 2018-32-0048
The aim of this study is to develop techniques which can be used to assess tire performance for a motorcycle. This approach focusses on using vehicle level performance parameters and transfer functions to assess tire performance. Several vehicle level dynamic parameters and transfer functions like cornering speeds, lateral acceleration, roll angles and roll rates, roll transfer function, lateral acceleration factor respectively are used to understand the effect of tires on motorcycle dynamic behavior. Tire behavior is then studied by assessing maneuverability of the motorcycle in maneuvers like slalom and lane change. A subjective assessment is then performed to understand rider’s feedback and relate the same with objective findings. Interesting results on the relationship between subjective perception of the riders, tire force characteristics and objective measurements are presented. It is found that subjective perceptions on tires are majorly focused on grip, maneuverability and stability of the motorcycle. It is shown that tire grip feel can be captured using cornering speeds, lateral accelerations and decelerations measured in this study. It is found that subjective perceptions related to maneuverability like steering effort, responsiveness or agility and feedback perceived by the rider are significantly influenced by tires and they can be estimated through steering torque, roll transfer functions and lateral acceleration factors. It is found that tires giving good feedback to riders generate a sudden increase in steering torque while reaching cornering limits. This finding is very significant as it directly relates to the confidence perceived by the rider while cornering. Further, influence of tires on high speed stability of the motorcycle is presented and it is found that the impact of tires is more dominant on maneuverability when compared to high speed stability.
Barath Mohan, Sai Praveen Velagapudi
TVS Motor Company, Hosur, India
SAE/JSAE Small Engine Technology Conference