Drexel University, Department of Electrical and Computer Engineering, Philadelphia, 19104, USA.
Aix Marseille University, CNRS, ISM, Marseille, France.
Sci Rep. 2018 Mar 20;8(1):4868. doi: 10.1038/s41598-018-23150-7.
When we touch an object, complex frictional forces are produced, aiding us in perceiving surface features that help to identify the object at hand, and also facilitating grasping and manipulation. However, even during controlled tactile exploration, sliding friction forces fluctuate greatly, and it is unclear how they relate to the surface topography or mechanics of contact with the finger. We investigated the sliding contact between the finger and different relief surfaces, using high-speed video and force measurements. Informed by these experiments, we developed a friction force model that accounts for surface shape and contact mechanical effects, and is able to predict sliding friction forces for different surfaces and exploration speeds. We also observed that local regions of disconnection between the finger and surface develop near high relief features, due to the stiffness of the finger tissues. Every tested surface had regions that were never contacted by the finger; we refer to these as "tactile blind spots". The results elucidate friction force production during tactile exploration, may aid efforts to connect sensory and motor function of the hand to properties of touched objects, and provide crucial knowledge to inform the rendering of realistic experiences of touch contact in virtual reality.
当我们触摸一个物体时，会产生复杂的摩擦力，帮助我们感知表面特征，从而帮助识别手中的物体，同时也便于抓握和操作。然而，即使在受控的触觉探索中，滑动摩擦力也会剧烈波动，目前尚不清楚它与手指与表面的形貌或接触力学有何关系。我们通过高速视频和力测量研究了手指与不同凸起表面之间的滑动接触。根据这些实验，我们开发了一个摩擦力模型，该模型考虑了表面形状和接触力学效应，能够预测不同表面和探索速度下的滑动摩擦力。我们还观察到，由于手指组织的刚度，在凸起特征附近，手指和表面之间会出现局部断开的区域。每个测试的表面都有一些区域从未被手指接触过；我们将这些区域称为“触觉盲点”。这些结果阐明了在触觉探索过程中摩擦力的产生，可能有助于将手的感觉和运动功能与被触摸物体的特性联系起来，并为在虚拟现实中呈现真实的触觉接触体验提供关键知识。
