Development of an index for the sound and haptic quality of a seat belt

This study developed an objective method for evaluating the pulling perception when a passenger pulls on the seat belt of a car seat. Physical quantification was required to objectively evaluate the pulling perception of a seat belt (PPOSB) in a vehicle. This physical quantification was called the metric. This metric had to be correlated to the subjective rating for the PPOSB in a vehicle. In the study, a force metric was extracted from the pulling force measured using a specific robot, and a sound metric was calculated from the interior sound when a passenger pulled a seat belt. In order to find the correlations between these metrics and the subjective rating of the PPOSB, two subjective evaluations were performed for the seat belts of the 18 commercial vehicles used for the test. One evaluated the subjective pulling perception in relation to the pulling force of a seat belt, and the other evaluated the pulling perception in relation to the interior sound when a passenger pulled a seat belt. Two indexes were required to objectively evaluate the PPOSB: a force index to objectively evaluate the pulling perception for the pulling force and a sound index to objectively evaluate the pulling perception for the interior sound. These indexes were developed using linear regressions between two metrics and two subjective ratings. The developed indexes were successfully used for an objective evaluation of the PPOSB, with the goal of modifying seat belt components.