Rolling road system design for the RuotaVia test rig

The behaviour of road vehicle suspension systems has a considerably important effect over the overall performance, controllability, safety and comfort of modern vehicles. As a consequence of its importance, specific testing procedures and facilities have been developed, allowing a deeper understanding of the behaviour of vehicle suspension systems and tires. The RuotaVia Test Rig, located at the Laboratory for the Safety for Transport (L.A.S.T.) of Politecnico di Milano, allows the study of the vibration performance of suspension systems, by introducing a cyclic disturbance to a single wheel rotating over a steel drum. The necessity of further developing the vibration analysis requires a more advanced simulation of the suspension’s behaviour, and therefore introducing the rotation of an additional wheel during testing became a necessity. A rolling road system was specifically designed to fit the requirements of the RuotaVia facility, allowing the simultaneous rotation of both wheels (left and right) of a single vehicle axle. In order to support the second wheel some design alternatives were studied and their feasibility was analyzed. Finally an externally pressurized air bearing was designed to pneumatically support a rotating POLY-V rubber belt over which the vehicle tire rotates. The bearing supports the load over the rubber belt while significantly reducing the friction and the required driving power of the rolling road system.