We report an improvement of an instrument used to correlate perceived material surface characteristics to vibrations induced in a transducer via surface profile tracing by addition of stick-slip vibration and stochastic measurements. Our instrument utilizes an inductive transducer and turntable stage to measure and characterize induced vibrations, and additionally incorporates an elastic bead of poly(ethylene-co-vinyl acetate) (EVA) on the stylus tip to simulate the slight tackiness and elasticity of skin, when in contact with certain types of materials. It is thus able to tease vibrational frequencies out of the measurement through stick-slip friction from the polymer’s elasticity and tackiness. The result is a larger range of measurable frequencies of vibration from both normal and tangential forces, for use in classification of selected materials, that vary uniquely with roughness, speed of measurement, contact forces, and material compositions. Additionally, to simulate varying pressure during stroking of a material surface with a finger-tip, the turntable was warped to induce a periodic wobble. This wobble produces variations in contact friction over each period of the measurement by varying contact area and contact force, and thus increases consistency of measurements via statistical distributions of contact force and area. The distributions that manifest are high frequencies over a single period of measurement that can be parsed for classification purposes. The results of this work show that the improved instrument has significantly more data characteristics to utilize and can identify subtle differences between similar materials in identical environments.

我们报告了一种仪器的改进，该仪器用于通过添加粘滑振动和随机测量来将感知到的材料表面特性与通过表面轮廓跟踪在换能器中感应的振动相关。我们的仪器利用感应换能器和转盘台来测量和表征诱发的振动，并在测针尖上还加入了聚（乙烯-乙酸乙烯酯-乙烯-乙酸乙烯酯）（EVA）的弹性珠，以模拟皮肤的轻微粘着性和弹性。与某些类型的材料接触。因此，它可以通过粘滑摩擦从聚合物的弹性和粘性中挑出振动频率。结果是法向力和切向力可测量的振动频率范围更大，用于选择材料的分类，随粗糙度，测量速度，接触力和材料组成而异。另外，为了模拟用指尖抚摸材料表面时的压力变化，转盘会发生翘曲以引起周期性的摆动。通过改变接触面积和接触力，该摆动会在每个测量周期内产生接触摩擦的变化，从而通过接触力和面积的统计分布来增加测量的一致性。表现出的分布是单个测量周期内的高频，可以将其解析以用于分类目的。