Wearable finger pad deformation sensor for tactile textures in frequency domain by using accelerometer on finger side

Abstract

In this study, we set out to develop a method for estimating the fine and fast shear deformation of a finger pad, that is, the palm side of a fingertip, as it scans the surface of a material. Using a miniature accelerometer, we measured the acceleration at the radial skin, the deformation of which is accompanied by the shear deformation of the finger pad. Using a transfer function, as specified in a separate experiment, between the pad and side of a finger, we estimated the shear deformation of the finger pad in the frequency domain. A comparison between an estimate based on the accelerometer and another based on a precise force sensor for the tangential component of the interaction force between the fingertip and material surfaces showed that the estimation accuracy was sufficient for frequencies in excess of approximately 20-50 Hz and for skin deformation above 10 −6 m. Our technique merely requires that an accelerometer be attached to the side of the fingertip, which allows active texture exploration. These estimates or measurements of the finger skin deformation caused by touching materials will help us to comprehend the relationships between material surfaces and the resulting texture sensations.

A Universal Volumetric Haptic Actuation Platform

“…Similar to our prototype, other earlier studies have successfully expressed the deformation of the fingertip's skin as caused by the tangential force on the fingertip by using a spring-mass-damper model [44][45][46], thereby indicating a linear relationship between the deformation and force. This assumption holds provided that the skin deformation is insignificant and the normal load on the finger is constant, which has typically been observed and recorded during exploratory procedures (EPs) [23].…”

What the Mind Can Comprehend from a Single Touch

“…However, the simulated sensation was not perceived as realistic when the button was pressed too fast. Additional research demonstrated that the deformation of the skin caused by the tangential force on the fingertip can be expressed by using a spring-mass-damper model, indicating a linear relationship between deformation and force [39]. Research by Kaaresoja at Nokia focused on the implementation of vibrotactile feedback accompanied by visual and audio feedback to find latency thresholds required to make virtual button presses feel natural [40].…”

Tactile Texture Display with Vibrotactile and Electrostatic Friction Stimuli Mixed at Appropriate Ratio Presents Better Roughness Textures

“…This result implies that the deformation of the finger pad's skin along the normal direction mainly determined by surface asperities and the tangential deformation caused by friction may play different roles in texture perception [18,40]. One-dimensional quantities pertaining to skin deformation were measured in many studies related to the normal deformation [6,56], tangential deformation [13,45,48,57], or whole finger vibration [51], where skin deformation and texture perception were discussed. The information related to deformation or vibration in different dimensions is closely coupled, because they propagate in the fingertip.…”