A hierarchically patterned, bioinspired e-skin able to detect the direction of applied pressure for robotics

Abstract

Tactile sensing is required for the dexterous manipulation of objects in robotic applications. In particular, the ability to measure and distinguish in real time normal and shear forces is crucial for slip detection and interaction with fragile objects. Here, we report a biomimetic soft electronic skin (e-skin) that is composed of an array of capacitors and capable of measuring and discriminating in real time both normal and tangential forces. It is enabled by a three-dimensional structure that mimics the interlocked dermis-epidermis interface in human skin. Moreover, pyramid microstructures arranged along nature-inspired phyllotaxis spirals resulted in an e-skin with increased sensitivity, minimal hysteresis, excellent cycling stability, and response time in the millisecond range. The e-skin provided sensing feedback for controlling a robot arm in various tasks, illustrating its potential application in robotics with tactile feedback.

Large‐Area Fabrication of High‐Performance Flexible and Wearable Pressure Sensors

“…Unlike most of the reported pressure sensors with top-bottom electrodes, [1,4,8,9,12,16,[18][19][20][21][22][23][24][25] here, we propose a printable side-by-side electrode configuration (Figure 1b), which makes it easy to miniaturize the sensor format (4 mm × 2 mm, Figure 1c) and also easy to create sensor arrays with self-defined patterns. Unlike most of the reported pressure sensors with top-bottom electrodes, [1,4,8,9,12,16,[18][19][20][21][22][23][24][25] here, we propose a printable side-by-side electrode configuration (Figure 1b), which makes it easy to miniaturize the sensor format (4 mm × 2 mm, Figure 1c) and also easy to create sensor arrays with self-defined patterns.…”

“…Topbottom electrode configurations are the mostly reported sensor layouts with three common scenarios: 1) the pressure-sensing layer is sandwiched between two electrodes; [18][19][20][21][22][23] 2) a conductive pressure-sensing microstructure used as an electrode is paired with a flat counter electrode; [4,24,25] and 3) two conductive microstructures are interlocked with each other. Topbottom electrode configurations are the mostly reported sensor layouts with three common scenarios: 1) the pressure-sensing layer is sandwiched between two electrodes; [18][19][20][21][22][23] 2) a conductive pressure-sensing microstructure used as an electrode is paired with a flat counter electrode; [4,24,25] and 3) two conductive microstructures are interlocked with each other.…”

Bioinspired Prosthetic Interfaces

“…However, the pressure‐induced deformations at different directions cannot be distinguished from the electrical signal readouts, limiting the quantitative analysis at the microscopic level. To address this limitation, recently, Boutry et al reported a hierarchically patterned electronic skin for detecting multidirectional forces ( Figure a) . In contrast to previous designs, this biomimetic skin adopted a 3D top and bottom electrode to mimic the epidermis–dermis interface, while leaving the dielectric film unstructured.…”

Bioinspired Triboelectric Nanogenerators as Self‐Powered Electronic Skin for Robotic Tactile Sensing

“…[34] The fingerprint patterns on skin enable sensitive perception of fine stimuli through amplification of vibrotactile signals, [35] while the interlocking microstructures between the epidermal and dermal layers can amplify and efficiently transfer tactile stimuli to cutaneous mechanoreceptors. [39] However, the fabrication methods adopted by those studies typically involved sophisticated fabrication procedures including lithography and etching. [38] Boutry et al proposed an interlocking structure for the fabrication of capacitive e-skin sensors to distinguish the direction of applied pressure.…”