The main idea from this paper is show a method to correlate the driver's subjective vibrational perception to numeric values of acceleration measured in the steering wheel. These studies came from a task realized during the development of a vehicle current in production. During the development period of this vehicle, a specific vibration was verified by subjective evaluations in the steering wheel, presenting a rotational movement. The intensity of this vibration is considered not acceptable considering the final consumer perception. From this assumption, a simplified method was used to measure this vibration and after this correlate it to the drivers' perception. The method consists in measuring the acceleration in the Y axis, tangent to the steering wheel, with the accelerometer at 12:00h position. This point was elected to install the accelerometer because shows basically the vibration to be studied and the steering wheel is the main interface between vehicle and driver for this issue (based on ISO 2631)[5]. So the acceleration values were correlated to the subjective evaluation rates (based on SAE J 1060)[8].
As additional consideration, the correlation between the values measured and perceived was studied and verified using some concepts of the psychophysics. As a result, a correlation curve was generated and with the information, ranges of vibrational acceleration were set to guide the studies with correct human perception limits to avoid any drivers complains. With these data and conclusions, the limits for tires non-uniformity were reset to assure the driver does not face the vibration and be complained.