Haptic perceptions in the vehicle seat

The perceptual overloads of visually and auditorily based information and their interference phenomena within vehicles led to research for the applicability of haptically based information and the haptic interfaces to intelligent vehicles. Because seats are the interface that touches the largest area of the driver's body, the driver's seat in vehicles has been the focus of a promising haptic interface that can improve the safety of drivers and the effectiveness and efficiency of the information transfer between vehicles and drivers. This study aims to provide practical guidelines as a building block for designing the haptic (or vibrotactile) interface in a vehicle's driver's seat by investigating, through four experiments, 1) proper intensity of vibration, 2) minimum distance of spatially distinguishable vibrations, 3) proper position and direction of vibration, and 4) proper rhythm of vibration. Twenty participants took part in the experiments, which were conducted in driving simulation environments. These environments consisted of a real car seat, commercial vibration actuators (i.e., the eccentric motors), and a monitor that showed scenes of the road while driving. This study recommended the proper intensity (approximately 26 to 34 Hz and 2.0 to 3.4 G), position (seat pan or back support), direction (horizontal or indirect), intervibration distance (8 to 9 cm), and rhythm of vibration (3-s duration with 0.5-s interval), and showed how the characteristics of drivers, such as gender and age, had effects on setting the design variables of the haptic interface in the vehicle seat.