Electrospinning Machine | Bio-Inspired SA-FA Bionic Dual Receptor Electronic Skin for Intelligent Gesture and Material Cognition Systems Enhanced by Static-Dynamic Mutual Interaction

Research Background
With the rapid development of artificial intelligence, flexible electronics, and robotics, electronic skin (e-skin), as an important interactive interface connecting the virtual world and the real world, has received widespread attention. The reason why human skin can achieve highly complex tactile cognition relies on two key types of mechanoreceptors: slow-adapting (SA) receptors (such as Merkel cells), sensitive to sustained pressure, capable of detecting and maintaining stable signals; fast-adapting (FA) receptors (such as Meissner's corpuscles, Pacinian corpuscles), sensitive to rapidly changing mechanical stimuli, suitable for perceiving light touch, vibration, and transient changes. This synergy of SA and FA dual receptors constitutes the core mechanism of human touch, enabling us not only to perceive the external environment but also to recognize and judge objects (such as material hardness, surface texture, object category). 

In recent years, inspired by the human tactile system, researchers have developed various bionic electronic skin architectures: piezoresistive, piezoelectric, and capacitive electronic skins, mainly simulating SA receptors for sustained pressure and stress detection; triboelectric and piezoelectric electronic skins are mostly used for the bionic function of FA receptors, capable of rapid response to vibration and transient stimuli. However, most of these works are limited to imitating the function of a single receptor, making it difficult for the system to achieve comprehensive acquisition of multi-dimensional tactile information, let alone autonomous learning and higher-order cognition. Especially in tasks such as gesture recognition and material hardness/softness perception, single-mode electronic skins often have: limited recognition accuracy, insufficient stability in complex environments; insufficient usability demonstration, often relying on external auxiliary signal processing; lack of autonomy, lacking multi-dimensional integration and high-level interpretation of tactile information. In this context, how to construct a bionic dual-receptor electronic skin with both SA and FA functions, and achieve autonomous perception and cognition of multi-dimensional tactile information through integrated hardware and software design, has become a core problem urgently needing breakthrough in the field of electronic skin and intelligent robotics.

Research Findings
Although existing studies have attempted to achieve diversified perception in electronic skin through various mechanisms such as capacitance, piezoresistance, and triboelectricity, most solutions remain limited to acquiring single-modal tactile information, making it difficult to support autonomous cognition in complex environments. For instance, capacitive-based sensors excel in sustained pressure detection but exhibit insufficient response to transient signals; triboelectric and piezoelectric devices enable rapid response but lack stable static perception capabilities. The limitations of this "single perception mode" result in significant gaps between existing systems and human skin in terms of robustness in gesture recognition, accuracy in discriminating material hardness/softness, and autonomy in multi-dimensional information fusion.

To break through this bottleneck, a team led by Professor Li Yang from Shandong University, in collaboration with teams from Kwangwoon University, Korea and the University of Jinan, proposed a bionic SA-FA dual receptor (BDR) electronic skin, which deeply integrates the functional characteristics of SA and FA through a static-dynamic interaction enhancement mechanism, achieving the unification of stable pressure detection and rapid transient response in a single device, laying the foundation for the development of electronic skin entering the "cognitive level". This electronic skin consists of two parts: an ionic hydrogel micro-pyramid structural unit (mimicking SA receptor), with a linear sensitivity of up to 172 kPa⁻¹ (30 kPa range), response/recovery time of only 11.2 ms, and a detection lower limit as low as 0.5 Pa; an electrospun TPU/mica fiber triboelectric unit (mimicking FA receptor), with excellent self-powered characteristics and material identification capabilities. Based on this innovation, the research team built two systems to verify its performance.

Intelligent glove cognitive system: Using dual-channel signals of capacitance and voltage, combined with a deep neural network (DNN), it achieved accurate recognition of 7 sign language actions, with an average accuracy of 99.3%, and can drive a robotic hand in real time to complete complex interactions. Intelligent autonomous material cognitive system: Integrating the BDR electronic skin into a robotic finger, combined with a 1D-CNN algorithm, it can identify the electronegativity, hardness/softness, and category of materials (Ecoflex, PVDF, HDPE, paper, PET, PU) with just one touch, with an average accuracy of 96.2%, and can display them in real time on a visual interface. The related results were published in the international journal "Advanced Science" under the title "Bio-Inspired SA-FA Bionic Dual Receptor Electronic Skin for Intelligent Gesture and Material Cognition Systems Enhanced by Static-Dynamic Mutual Interaction". Dr. Li Hao from Shandong University is the first author. Professor Niu Hongsen from the University of Jinan, Professor Nam-Young Kim from Kwangwoon University, Korea, Professor Eun-Seong Kim from Kwangwoon University, Korea, and Professor Li Yang from Shandong University are the co-corresponding authors.

Figure 1. Structure diagram of the intelligent tactile cognitive system based on BDR electronic skin.

Figure 2. Piezocapacitive characteristics of the BDR electronic skin.

Figure 3. Triboelectric characteristics of the BDR electronic skin.

Figure 4. Demonstration of the intelligent glove cognitive system.

Figure 5. Demonstration of the intelligent autonomous material cognitive system.

Literature link: Bio-Inspired SA-FA Bionic Dual Receptor Electronic Skin for Intelligent Gesture and Material Cognition Systems Enhanced by Static-Dynamic Mutual Interaction
https://doi.org/10.1002/advs.202509740