MBike : a free software implementation of a multibody motorcycle model

In this thesis the dynamic of a motorcycle is analysed using the multybody approach. The model represents a full motorcycle with 10 rigid bodies. A rigid ring tyre model that represent the behaviour of a motorcyccle tyre has been implemented and represent the main focus of the thesis. Contact forces are modelled with a Pacejka steady-state model, parameters are obtained by fitting data from tests conducted on an MTS flat track test machine. Rider behaviour is simulated by means of three PID controllers acting on the steering torque and torque to the rear wheel, The rider model is an open loop model. Aerodynamic forces have been taken into account by means of a CFD analysis in order to obtain the aerodynamic characterisation of the motorcycle’s body. Stability analisys has been conducted in steady state condition without the influence of the rider model. The software used for the simulation is MBDyn, an open source general pourpose multybody dynamic software and the model is released under GNU-GPL license1, making it the first, to the author’s knowledge, publicly available multibody free motorcycle model.