Optimisation of off-road motorcycle suspensions

Off-road motorcycle suspensions are subjected to severe solicitations like large jumps and bumps. Its optimisation requires assessing comfort and handling for which several indices can be found in the literature. However these indices were developed for other vehicles and it is not clear how they behave assessing large obstacles. To investigate this, four comfort indices and four handling indices are used to assess the performance of a motorcycle modelled with two degree of freedom under continuos and impulsive off-road excitations. It is found that the best suited indices are the Vibration Dose Value for comfort and the eighth order mean value of the contact force for handling. Additionally, these indices are used to optimise the damping on a five degree of freedom model of a motorcycle, with which is found that on each road scenario, the optimal damping is in between the damping for optimal comfort and optimal handling, and the final selection depend on the relative preference between both objective