A ride comfort analysis of two-wheeled veichles is discussed in this work. A series of experimental tests were performed in relation to roads having different surface roughness; employed vehicles, differing on motorization, suspensions and wheel sizes, were instrumented with two axes (longitudinally and vertically oriented) accelerometers, fixed at the human-vehicle interfaces. Moreover, two axes accelerometers were also fixed to the wheel hubs, in order to record road inputs at each wheel.
The comfort analysis, which was conducted following the international ISO 2631, allowed the influence of the primary vehicle suspension system to be investigated.
In addition, a multibody model of the scooter-pilot system was built using Adams© code, for one of the employed vehicles, with the main aim of assessing the effectiveness of a dynamic simulation of ride comfort. Road roughness was simulated by imposing the vertical and longitudinal displacements at the front and rear wheel hub, which were determined by a proper developed procedure, on the basis of the corresponding experimental vertical and longitudinal accelerations. So far, the human body was mainly considered as rigid and connected by visco-elastic constraints to the scooter handle bar. Obtained results showed a great influence of the elastic properties of the handle constraints on the simulated handle bar accelerations; however, a fairly good agreement was observed between the comfort indexes obtained on the basis of experimental data and dynamic simulation.
In the final part of the work the frequency response function of the scooter driver system was investigated on the basis of parametric identification methods. The horizontal and vertical wheel hub accelerations were considered as system inputs, while the acceleration measured at one of the recording points, was considered as the system output. The so determined frequency response function were able to accurately reproduce the vibration levels at the driver interface points.