Quantification of Human Discomfort in a Vehicle Using a Four-Post Rig Excitation

Abstract

The ride comfort of a vehicle is a vital aspect determining competitiveness of vehicles. The comfort is intricately related to feelings of discomfort due to vibration. The discomfort depends on various dynamic aspects of the suspension-seat and surrounding system. In industry, the discomfort due to vibration is assessed by road testing on various surfaces; these road tests may not be accurately repeatable. Discomfort, in general, can be assessed by measurements based on a shaker table and seat combination. These results when used for “in vehicle situations” may not accurately indicate the level of human discomfort in a vehicle. In view of this, to quantify seated human discomfort in a vehicle, measurements were performed using a four-post rig simulator; the setup allows controlled in-situ experiments to be conducted. A group of six subjects were exposed to sinusoidal vibration at five magnitudes in the vertical direction for heave, roll and pitch motion. The objective is to develop a discomfort metric which could be used to compare vehicles. The preliminary results show varying significance of roll, pitch and heave motion. The results, however, confirm the nonlinear variation of perception as a function of the physical stimulus. The test setup can be used to study the effects of complex road inputs and eventually may contribute towards reduced reliance on road tests.