Motorcycle dynamic stability monitoring during standard riding conditions.

The target of the research is to improve driver safety related to dynamic instability, often cause of accidents involving powered two-wheeled vehicles as explained in the “UNECE Transport Review of Road Safety”. The paper explains the feasibility study of an Advanced Driver Assistance System (ADAS) with regards to the real-time instability conditions identification of a generic motorcycle during standard riding conditions. As well known, these types of systems have been typically applied and relied on in the automotive sector, but they have not yet broken through for two-wheeled vehicles. An initial study of the vibration modes of a motorcycle led to the isolation of the weave mode and the wobble mode) as the most likely to occur during normal use. Having identified the damping factor of the vibration modes as a possible instability index, various methods have been studied to estimate the frequency and damping coefficients of the weave and wobble modes. The methods considered include both one DOF system methods and a multi DOF system method. Each of these have been evaluated on a numerical time history and an experimental time history. In particular the accuracy, robustness, time efficiency and ease of implementation have been considered as a priority in choosing the most effective method. A logical procedure with which a possible dynamic instability can be identified is therefore reported and explained. The developed intelligence has been integrated in an offline diagnostic software that processes signals acquired by sensors placed on the motorcycle during running. Using this algorithm logic two very different motorcycles have been studied and a comparison between experimental and numerical results are shown. The proposed methodology has also been implemented in a GUI (Graphical User Interface), whose scope is to emulate the real-time application of the algorithm logic to standard running conditions. (Author/publisher) For this paper, other papers and posters presented at this Symposium see http://bicycle.tudelft.nl/bmd2010/