대형 버스의 승차감 평가에 관한 연구

Ride comfort is one of the most important performance indices which decide the quality of a vehicle. If we can predict the performance of ride comfort by using computer simulations, the time and effort needed to improve ride comfort can be saved. A full vehicle model for a large bus with air suspension was developed, including nonlinearities of hydraulic damper and air suspension. Simulations were performed with this model to predict the ride comfort by using the 7DOF full car model. To evaluate ride comfort in vehicle dynamics, it is essential to describe a road surface profile precisely. We used a spatial domain power spectral density function method to generate road surface profiles. Field tests were performed using both bump road and real road conditions. RMS(Root Mean Square) values for a bump road and WRMS(Weighted RMS) of PSD(Power Spectral Density) and RSS(Root Sum of Squares) for random road were calculated and compared with the results of feeling tests. These comparisons showed that RSS gave good agreement with the results of feeling test, and can be used to evaluate the ride comfort for a vehicle.