SAE 2017-01-1563 : 2017

Two and three wheeler vehicles are largely used in many developing and under developing countries because of their lower cost, better fuel economy and easy handling. Although, the construction of them is simpler than the four wheeler vehicle, they pose some problems related to instability. Wobbling is the main cause of instabilities in two wheeler and three wheeler vehicles. In this study, a mathematical model was proposed and developed to determine wobble instability of a two wheeler. Nonlinear equations were formulated by using kinematics and the D’Alembert’s principle with the help of multi body formalism. The non-linear equations found in the study were linearized with respect to rectilinear and upright motion, considering no rolling. It led to formation of matrix. The real part of the Eigen value of the matrix was found to be negative, implication of whose was an asymptotic stable motion. It was observed that, the above real part of Eigen value was a function of different parameters such as Tire stiffness, Frame compliance, Steering angle and Rider’s way of handling. These parameters play an important role in determination of wobble frequency. Further, a model was developed using the Lotus Suspension Software, and dependency of above parameters on wobble frequency was studied. Further, experiments were conducted to verify the dynamics behaviour of these parameters included in the proposed mathematical model. The simulation and experimental results are presented in this paper.

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