Quantifying touch-feel perception on automotive interiors by a multi-function tribological probe microscope

In this paper we will report the preliminary study of people's subjective feelings on stroking surfaces of different materials and the measured properties of these surfaces, in order to understand exactly what properties matter and to what extent the different factors weight the human perception. Ten specimens with materials ranging from natural wood, leather to engineered plastics and metal were selected for this study. These specimens were first tested by a group of untrained people for describing their subjective feel sensation in terms of smooth-rough, soft-hard, slippery-grippy, warm-cold and overall judgement of like and dislike for the sample being touched. Then the same specimens were measured for their surface properties by various techniques. In particular, the multi-function measurement has been carried out on each of specimens by a novel tribological probe microscope (TPM). The TPM is capable of measuring four functions in a single scan to provide area mappings of topography, friction, Young's modulus and hardness. As the TPM mapping is based on a point-by-point scanning so values of the four measured functions are linked in space and in time, therefore cross correlation between functions can be established. Although the TPM measured area is small compared to fingertip, the results show that the perception is influenced by nano- and micro-scale structure of surfaces