When an alternating voltage is applied to the conductive layer of a capacitive touchscreen, an oscillating electroadhesive force (also known as electrovibration) is generated between the human finger and its surface in the normal direction. This electroadhesive force causes an increase in friction between the sliding finger and the touchscreen. Although the practical implementation of this technology is quite straightforward, the physics behind voltage-induced electroadhesion and the resulting contact interactions between human finger and the touchscreen are still under investigation. In this article, we first present the results of our experimental study conducted with a custom-made tribometer to investigate the effect of input voltage on the tangential forces acting on the finger due to electroadhesion during sliding. We then support our experimental results with a contact mechanics model developed for estimating voltage-induced frictional forces between human finger and a touchscreen as a function of the applied normal force. The unknown parameters of the model were estimated via optimization by minimizing the error between the measured tangential forces and the ones generated by the model. The estimated model parameters show a good agreement with the ones reported in the literature.

中文翻译：

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模拟电粘附下人手指与触摸屏之间的滑动摩擦

当向电容式触摸屏的导电层施加交流电压时，人的手指与其表面法线方向之间会产生振荡的电粘附力（也称为电振动）。这种电粘附力会增加滑动手指和触摸屏之间的摩擦力。尽管该技术的实际实施非常简单，但电压感应电粘附背后的物理原理以及由此产生的人手指与触摸屏之间的接触交互仍在研究中。在本文中，我们首先展示了使用定制摩擦计进行的实验研究的结果，以研究输入电压对由于滑动过程中的电粘附而作用在手指上的切向力的影响。然后，我们使用接触力学模型来支持我们的实验结果，该模型用于估计人类手指和触摸屏之间的电压感应摩擦力作为所施加法向力的函数。通过最小化测量的切向力与模型产生的切向力之间的误差，通过优化来估计模型的未知参数。估计的模型参数与文献中报道的参数非常吻合。