ABSTRACT
New indicators for riding comfort were studied using vehicle dynamics and mean panel rating. Two vehicle models were developed, one for a person car and another for a truck. Vehicle models were two axle rigid body models with seven degrees of freedom. Vehicle parameters were chosen so that the person car model and the truck model represented the most common vehicles in Finland. Twelve road sections totaling 61 km were measured using Destia’s high speed monitoring vehicle. A three dimensional surface was used as an input to the vehicle models. Responses were simulated with the speed corresponding the speed limits for each section varying from 50 km/h to 120 km/h. Twelve responses were simulated using the raw profile of both wheel paths with 10 cm interval and results were calculated with 10 m reporting interval. Nine responses of the simulation models were the displacement, speed and acceleration of bounce, rolling and pitching movements. For each response average, standard deviation and maximum were calculated. Three other responses were load transfer ratio, equivalent single axle load and the calculated amount of energy used in shock absorbers. The data from mean panel rating of 20 people were compared to the simulated responses. The conclusion of the study was that the standard deviations of the accelerations of bounce, roll and pitch of a truck were the best indicators to describe the riding comfort on a road. Bad sections had combinations of different indicators representing different roughness type.
