Modulation of Velocity Perception by Engine Vibration While Driving

Abstract

While driving a vehicle, perceiving velocity is important for appropriate operation and is one of the most important factors for preventing collisions and traffic congestion. In contexts where perceiving velocity changes is difficult, such as on an undulating road, the velocity may exceed the speed limit or traffic congestion may occur due to heavy braking to avoid a collision. Hence, we proposed a method of modulating the perception of velocity through tactile stimulation to promote adequate operation for the driver. In contrast to methods using visual and auditory stimulation, this method has advantages of not increasing the visual cognitive load, not disturbing the enjoyment of music, and reliably stimulating the driver. In this study, we constructed a velocity perception model based on vibrotactile stimulation induced by the engine speed and proposed a method of changing the vibrotactile stimulation by altering the shift position of the transmission to modulate the perception of velocity without additional vibration actuators, regardless of the actual velocity. We measured the seat and engine vibration using two different vehicles. The results demonstrated that the peak acceleration frequencies are proportional to engine speed, indicating that the vibration depends upon the engine speed, not the velocity. We implemented a method of changing the shift position in an actual vehicle and verified the feasibility of the method through a psychophysical experiment. The results showed that drivers perceived a higher velocity with increasing engine speed and lower velocity with decreasing engine speed.