Research On Flexible Self-powered Electronic Skin Sensing System

With the booming demands for health monitoring and human-computer interaction,e-skin has attracted extensive attention in academic circles,which imitates human skin sensory ability.However,the special application of the e-skin poses an unprecedented challenge to its power module.Nano-generator(NG)is a new type of energy harvesting and self-powered sensing technology,embedding it into e-skin is crucial to realize self-powered wearable electronic devices.In this paper,a novel flexible self-powered e-skin sensor system based on piezoelectric triboelectric-hybrid NG(PT-HNG)is proposed.The system can not only monitor physical signals in real time as a self-powered sensor,but also power other electronic devices as a DC regulated power supply.The main achievements and work of this paper are as follows:Firstly,the preparation methods of electrode materials,triboelectric functional materials and piezoelectric functional materials of e-skin sensor system were studied.On this basis,a simple single-electrode triboelectric NG(SE-TENG)and a piezoelectric NG(PENG)models were built and their electrical output characteristics were measured.The results show that the open-circuit voltage(Voc)and short-circuit current(ISC)of the SE-TENG reached?200V and?30nA respectively,and the VOC and ISC of the PENG reached?30V and?3?A respectively.Secondly,the structural model and working mechanism of the e-skin sensing system were discussed in deep.The key to the structural is to realize an all-directional stretchable electrode to meet the system requirements,the paper realized a flexible,stretchable and transparent e_skin sensing system by weaving the silver yarn into a"chain" fence like conductive network and embedding it into the functional material.Based on the working mechanism of SE-TENG and PENG,the working mechanism of e-skin system was analyzed in detail,and the rationality of the e-skin as a wearable device was proved.Thirdly,the theoretical derivation of the circuit model and the design of the peripheral rectifying circuit and voltage-stabilizing circuit of the e-skin sensor system were studied in deep.The control equations of the system were derived by mechanical modeling and equivalent circuit modeling,and the theoretical results were simulated by MATLAB,the results show that the theoretical curve and the test curve achieved a good consistency.Make the system be used as a 3.6V DC regulated power supply to power other electronic devices by designing a peripheral rectifying circuit and voltage-stabilizing circuit for it.Finally,the electrical output characteristics and sensing characteristics of the e-skin sensor system were tested on the experimental platform built by the project team.Electricity output characteristic results show that VOC of the e-skin almost completely contributed by the SE-TENG,up to?200V.ISC is the linear superposition of the SE-TENG's and PENG's,up to?3?A.Internal resistance(Rin)is about the SE-TENG's and PENG's in parallel,low to?1M?.Maximum output power(Pmax)is about linear sum of SE-TENG's and PENG,up to?17?W.In addition,the mechanical input signal and the electrical output signal of the system have a good linearity,indicating that it has a broad application prospects in sensing.