A Comprehensive Method to Assess the Ride Comfort of Vehicle

The paper presents a comprehensive method for objective vehicle ride comfort evaluation. The method is based both on a validated mathematical model of a human seated on board of a road vehicle and on a dummy reproducing the human whole body vibrations (WBV). The first part of the research includes experimental tests on instrumented seats for evaluating the stiffness and the damping of respectively the cushion and the backrest. Either an indoor vibrating table fitted with a vehicle seat and different instrumented vehicles (cars and light trucks) running on a test track have been used. The test track includes uneven road and obstacles. Human subjects have been chosen in order to obtain a high variability in the anthropometric features (height, weight, gender, age). Several tests have been also performed with the same subject submitted to the same excitation in order to investigate the intra-subject variability. During the study different seats have been compared. From the acquired data, a mathematical model of the human subject has been derived and numerically validated by minimizing the error between the measured and the computed accelerations. The model is able to predict the dynamic response of a seated human and can be used for the optimal design of seats or for seat evaluation purposes. A mechanical device corresponding to the model has been employed. The device (MaRiCo) is fully adjustable in order to simulate the vibrational behaviour of different human subjects. Particular attention has been devoted to the construction of the dummy to reduce as much as possible the friction between the moving components. The dummy rests on the seat by means of special elements that act as the tights and the back of a human subject. A numerical validation has been performed by means of the dummy.Copyright © 2008 by ASME