Experimental study of the influence levels of different vehicle seat adjustments on the fore-and-aft modal characteristics using the orthogonal array method

The vehicle seat modal characteristics (in particular, the first resonant frequency and the corresponding modal shape) play important roles in the seat design and the ride comfort. This paper investigated the relationship between the first modal characteristics and the positions of the adjusters on the vehicle seat. There are four adjusters on the vehicle seat to change its position so as to match the driver's somatotype, the driving and the sitting habits. Different seat positions inevitably cause changes in the resonant frequency. An orthogonal array method was adopted to evaluate the influence levels of the adjusters by using a Pareto chart. It was found that the first modal (fore-and-aft) shape is almost uninfluenced by the variations in the adjuster positions, whereas the first modal frequency is greatly influenced by the changes in the adjuster positions. The first modal frequency is most affected by the variation in the slider position, followed by the variation in the headrest adjuster position, the variation in the recliner position and the variation in the height adjuster position.