Research On Intelligent Self-Powered Human-Machine Interface System Based On Triboelectric Nanogenerator

The development of sensor technology,integrated circuit technology and communication technology accelerates the realization of the technical concept of"Internet of Everything".However,the energy supply issue of massive sensors and the environmental pollution problem caused by energy storage devices still need to be solved.Since the invention of triboelectric nanogenerator by Academician Zhonglin Wang et al.in 2012,its collection efficiency of"high entropy"energy such as environmental mechanical energy,wind energy and water energy has been continuously improved,which supports it to become a"clean"power supply for distributed sensors.Human-machine interface system is an important access for human to enter the"Internet of Everything".The self-powered sensing technology and energy collection technology based on triboelectric nanogenerator solve the problem of energy supply of human-machine interface devices.Therefore,the cross study of triboelectric nanogenerator and human-machine interface system is of great significance.In this dissertation,the applications of triboelectric nanogenerator in input device and energy collection device of human-machine interface system are studied.It mainly solves the problems of a large number of output channels and complex electrode topology of traditional handwriting recognition sensor with longitude and latitude array electrode and high equivalent internal resistance and low energy conversion efficiency of solid-liquid triboelectric nanogenerator.Specifically,for the human-machine interaction input device with sliding track detection and touch positioning function based on triboelectric nanogenerator,the key technical problems such as detection principle,electrode design and fabrication process are studied.The instantaneous discharging mechanism of solid-liquid triboelectric nanogenerator and droplet energy collection device based on the bulk effect are also studied to improve the collection efficiency of droplet energy and the power output to low input impedance load.The main innovative research contents of this dissertation are summarized as follows:（1）A flexible handwritten character detection device with a single output channel based on triboelectric effect combing the feature extraction and discrimination ability of convolution neural network is proposed.A design scheme of double helix electrodes is proposed,which converts handwriting action into triboelectric current output between two helix electrodes.The experimental results show that the convolution neural network can effectively extract the characteristics of the peak value and peak density of the triboelectric current output,and complete the effective discrimination of the input characters based on the feature learning of the training set samples.Based on the sliding window segmentation method for triboelectric signal preprocessing,the one-dimensional convolutional neural network designed in this dissertation achieves97%prediction accuracy in the recognition test with 7 letters,and 96.3%prediction accuracy in the user recognition test with 5 participants.Based on the freestanding mode of triboelectric nanogenerator,a theoretical model for measuring the interaction between device dimension parameter,handwriting trajectory characteristic and output signal is established to guide device design.A platform for real-time recognition of handwritten input characters is designed and built,which provides a reference example for the design of self-powered human-machine interface system based on convolutional neural network.（2）The touch and slide detection device based on triboelectric nanogenerator mainly adopts the longitude and latitude array electrode design scheme.Through the comparative analysis of the output signals on all electrode channels,the coordinate information of touch position can be obtained.This dissertation presents an improved longitude and latitude array electrode design scheme based on the resistor chain design method,which reduces the m+n output channels required by the traditional design scheme to 4,and effectively solves the problems of a large number of output channels and a large amount of output data in the traditional design scheme.Aiming at the problem of interlayer electrode interference in rectangular electrode design,an electrode design scheme based on complementary semicircular detection unit is proposed.The applications of electrospinning technology and plasma etching technology in the fabrication of triboelectric materials and the improvement of triboelectric performance are studied.A 40 mm×40 mm touch detection device prototype that can be applied to smart mobile electronics is designed and fabricated,which shows its application value in the field of human-machine interface device.（3）The typical internal resistance of triboelectric nanogenerator is between electromagnetic generator and piezoelectric nanogenerator,so its efficiency in supplying energy to low input impedance sensor is lower than that of electromagnetic generator.Aiming at the problem of low energy supply efficiency that triboelectric nanogenerator may encounter when driving distributed sensors and human-machine interface devices,an instantaneous discharging solid-liquid triboelectric nanogenerator is proposed.By analyzing the I-V-Q（current-voltage-charge）transfer theoretical model of single electrode solid-liquid triboelectric nanogenerator,it can be deduced that the opening and closing control of charge-discharge circuit in the process of voltage establishment can realize the instantaneous discharging effect based on the charge accumulation principle.The voltage-load resistance uncorrelation and RC discharge characteristics of the instantaneous discharging mode under different load resistances show that the instantaneous output power of the instantaneous discharging mode is much higher than that of the single electrode mode under low load.In the instantaneous discharging mode,the instantaneous output power is about 1700 times higher than that in the single electrode mode under the load resistance of 1 MΩ.A comparative experiment is designed to supply power to LEDs with a total resistance of 8 KΩby devices working in instantaneous discharging mode and single electrode mode respectively,which intuitively shows the advantages of instantaneous discharging technology in low load situations.（4）According to the requirements of wearable human-machine interface devices for raindrop energy collection,a solid-liquid triboelectric nanogenerator for sliding droplet energy harvesting is designed based on the bulk effect.The triboelectric output characteristics of nanogenerator based on bulk effect during droplet sliding are systematically studied.Thanks to the high utilization efficiency of triboelectric charge based on bulk effect,the designed device achieves a peak short circuit current output about 1000 times higher than that of the control device based on the single electrode working mode,and the droplet energy collection efficiency is increased from about2.1×10^-5%to 5.2×10^-2%.Combined with the equivalent circuit model,the multiform information such as droplet shape,droplet position,charge transfer and current output are comprehensively analyzed,and the output theoretical model of bulk effect-based triboelectric nanogenerator suitable for sliding droplets is established.Finally,a droplet energy harvester with array top electrode is designed and fabricated,which provides an example for the design of raindrop kinetic energy collection component of human-machine interface system.