DEVELOPMENT OF A NONLINEAR RIDE QUALITY MODEL TO AID IN TWEELå© PARAMETER SELECTION

The ride comfort of a vehicle is very important to both automotive and tire manufacturers. Unfortunately the ride comfort provided by the tire has an inverse relationship with the handling ability of the vehicle. Michelin has sought to decouple ride comfort and handling capability by developing a non-pneumatic tire they have dubbed the TWEEL©. To better understand what effects fitting a TWEEL with specific characteristics would have on the ride comfort of a vehicle a computer simulation was developed to study the effects of TWEEL stiffness and deflection on ride comfort. The vehicle model used in the simulation is a continuation and expansion of the linear vehicle model developed by Law [3]. The original model includes the following degrees of freedom: vertical motions of the front and rear axles, vertical and pitching motions of the sprung mass, and vertical motion of the engine. The original linear model was run and analyzed in the frequency domain. This work expands the previous work by treating both the shocks and the TWEELS as nonlinear elements. The nonlinear model was implemented in Simulink and run in the temporal domain. The data was analyzed in both the frequency and the temporal domain. The program outputs include the frequency response functions, the power spectral densities (PSDs) and root mean square (RMS) values for various outputs as well as channel data plotted against time. The ISO 2631 weighted RMS accelerations are plotted along with the ISO 2631 [1,2] comfort curves. Tire-to-road forces are also examined