Preliminary Study of Perceived Vibration Quality for Human Hands

A large body of knowledge exists regarding the effects of vibration on human beings; however, the emphasis is generally on the damaging effects of vibration. Very little information has been published regarding the effect of vibration on perceived consumer product quality. The perceived loudness of a product is quantified using the Fletcher-Munson equal loudness curves, but the equivalent curves for perceived vibration amplitude as a function of amplitude and frequency are not readily available. This “vibration quality” information would be valuable in the design and evaluation of many consumer products, including automobiles. Vibration information is used in the automobile design process where targets for steering wheel, seat track, and pedal vibration are common. For this purpose, the vibration information is considered proprietary and is generally applicable to a narrow frequency range. In this investigation, work paralleling the original Fletcher-Munson study is presented. “Equal comfort curves” for vibration were measured and developed for hands grasping a handlebar. A paired-comparison test methodology was used to establish an equivalency of perceived vibration comfort for vibration in a wide range of vibration amplitudes over a wide range of frequencies. The results include preliminary equal comfort curves for hand vibration, preliminary minimum perceivable vibration curves, and recommendations for a test to provide more definitive results.