A Highly Sensitive Tactile Sensor Using a Pyramid‐Plug Structure for Detecting Pressure, Shear Force, and Torsion

Abstract

through the discrimination of multiple mechanical stimuli. [3] Therefore, the ideal artificial electronic skin can discriminate external loads from various types of input and can also detect intensity.Furthermore, the electronic skin must have properties that satisfy corresponding requirements for tactile sensing. For example, there are several relevant para meters that electronic skin sensors must measure, such as sensitivity, working range, detection time, and hysteresis. The measurement of these is important in order to realize the tactile sensing of human activities or motions. To demon strate electronic skin with the capabili ties of humanskinlike tactile sensing, many researchers have studied novel materials with improved sensing perfor mance, including carbon nanotubes, [6][7][8][9][10][11][12] flexible elastomers, [3,4,6,[13][14][15][16][17] conducting polymers, [14,18,19] ionic gels, [5,7,[20][21][22][23] nanowires [24] or materials with the structure of nanoneedles, [25] hemispheres, [3,5,26,27] and pyramids. [10,14,[28][29][30][31] However, most of the previous studies have focused on the capability to perceive only a single type of mechanical stimulus, rendering previous attempts at designing an electronic skin incapable of sensing multiple forms of mechanical loads.Previous studies have reported sensors with different mate rials and structural approaches for the detection and discrimi nation of the perception of multiple mechanical stimuli. Yin et al. developed the fiber strain sensor for tensile, bending, and torsionsensitive properties using graphenebased composite fiber. [32] In the present study, a fiber strain sensor was fabri cated in a compression spring structure through a facile solu tion process with high reproducibility. Pang et al. presented an interlockingbased straingauge sensor for detecting multiple mechanical forces (including normal, tangential, and torsional forces) using Ptcoated microhair arrays. [33] This strain sensor allowed for a simple and robust sensing platform using the interlocking structure for largearea sensing. Despite the poten tial of devices such as these, the sensors presented in previous reports exhibited low sensitivity for the perception of external mechanical stimuli in a low sensing range with only small elec trical signal differences. They could also only detect a limited range of mechanical loadings.To improve the performance of tactile sensors, a new tac tile sensor should be designed by taking different approaches than the traditional approaches. In this study, we fabricated a tactile sensor composed of an ionic gel inspired by the ionic Sensors that detect and discriminate external mechanical forces are a principal component in the development of electronic tactile systems that can mimic the multifunctional properties of human skin. This study demonstrates a pyramid-plug structure for highly sensitive tactile sensors that enables them to detect pressure, shear force, and torsion. The device is composed of pyramidpatterned ionic gel inspired by neural mec...

Flexible Tactile Electronic Skin Sensor with 3D Force Detection Based on Porous CNTs/PDMS Nanocomposites

“…Compared with silicon-based devices with high hardness and effective Young's modulus, flexible materials are more suitable for bionic tactile applications due to the good adherence, tensility and flexibility [9][10][11]. A variety of flexible materials such as polyethylene (PE) [12], polydimethylsiloxane (PDMS) [13,14], polyurethane (PU) [15] and polyimide (PI) [16] have been applied to tactile sensors, and the operational principles of tactile sensors mainly include piezoresistive [17][18][19], capacitive [20], piezoelectric [21] and optical [22]. Among them, piezoresistive tactile sensors have been widely used, benefited from their uncomplicated and reliable fabrication process, low cost and application prospects in large area.…”

Motion Detection Using Tactile Sensors Based on Pressure-Sensitive Transistor Arrays

“…For these reasons, various channel materials and elastomeric dielectric materials have been studied for the development of the higher pressure-sensitive gate dielectric capacitances. The characteristics of the dielectric and channel materials and the results of the modification of the dielectric layer are summarized in Figure 6 [ 16 , 93 , 94 , 95 , 96 ] and Table 2 [ 55 , 93 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 ], respectively. Sujie Chen and co-workers proposed a method of one-step processing for a large area microstructure elastomer film that had highly-integrated microfeatures of the air gap ( Figure 6 a).…”

“…D. Choi and co-workers used a pyramid-plug structure to detect normal force, shear force, and torsion. By utilizing pyramid-shaped engraved electrodes and ionic gel as neural mechanoreceptors, each mechanical force has its own deformation mechanism, as shown in Figure 7 d [ 101 ]. Similarly, J.…”

“…Copyright 2018, Nature Communications. ( d ) Reproduced with permission [ 101 ]. Copyright 2019, Advanced Materials Technologies.…”

Highly Sensitive Tactile Shear Sensor Using Spatially Digitized Contact Electrodes

“…For the actual application of these tactile sensors to robotics or biomedical equipment, however, they must be reliable and be able to detect shear and slip, as well as contact pressure, making object manipulation or tactile discrimination possible. There have been sensors developed that detect vertical pressure and lateral shear forces simultaneously, but this simultaneous detection made it difficult to distinguish the signals [11,12,13,14]. To resolve this issue, sensor systems have been developed to distinctively sense shear force using separate dedicated sensors that are integrated into the system.…”