Bionic Research Of Mechanical Sensing Elements Inspired By Venus Flytrap Hair Sensilla

In the modern information society,sensor technology has become an important basis and driving force for the development and progress of a country,and it is also the essential key technology for human beings to explore the universe and step into space.As the core component of sensor technology,sensors have been widely used in manufacturing,medical industry,internet industry and aerospace industry,etc.,which has penetrated into all aspects of people’s lives and become an important cornerstone of social stability and development.Therefore,it is of great significance to improve the performance of existing sensors and explore the design principle and preparation technology of new generation sensing elements.In nature,creatures also have various sensory systems with similar functions to artificial sensors,which can achieve the acquisition and conversion of external information,so as to help creatures judge the surrounding environment.As a typical representative of carnivorous plants,the hair sensilla of Venus flytrap perfectly realizes the organic combination of high perceptual accuracy and micro-scale characteristics,and can accurately and quickly sense the mechanical stimulation caused by insects weighing 3mg.Therefore,exploring the excellent performance of Venus flytrap hair sensilla and carrying out the corresponding bionic research can provide important theoretical basis and inspiration for improving the performance of the existing sensors.In this paper,B52 Venus flytrap was selected as the bionic prototype.Combined with the principle of bionics,the sensitive sensing mechanism of the hair sensilla of Venus flytrap was revealed by experiments and theoretical analysis.The mathematical and physical models of bionic sensing element based on Venus flytrap hair sensilla was established.Bionic sensing elements with different parameters based on hair sensilla are designed and fabricated,and the corresponding application research is carried out.The main work of this paper is as follows:Firstly,the distribution,external morphology,deformation response,internal microscale structure and tissue mechanical properties of the Venus flytrap hair sensilla were analyzed by super depth of field microscopy,scanning electron microscopy,atomic force microscopy and computed tomography.The results showed that the hair sensilla of Venus flytrap was cantilever structure,which was mainly composed of rigid lever,flexible podium and constrained region between them.Both the lever and podium tissues are composed of tubular cells,while there are sensory cells in the constrained region besides tubular cells.The podium will bend while the lever will deflect if the hair sensilla is subjected to a load.The elastic modulus of the lever is one to two orders of magnitude larger than that of the podium on a same hair sensilla.The test results of the elastic coefficient of the cantilever structure of hair sensilla also show that the hair sensilla has a high sensitivity to the force.On this basis,the principle of the sensory process of Venus flytrap hair sensilla to external stimuli was analyzed.Then,based on the morphological structure and tissue material parameters of the Venus flytrap hair sensilla,the mathematical and physical models of bionic sensing element with cantilever beam structure was established on the basis of the biological model of Venus flytrap hair sensilla by using the principle of coupled bionics.The static characteristics and structural stability of the structure are analyzed by mathematical formula calculation and finite element analysis.It can be found that the bionic sensing elements imitating the hair sensilla can effectively concentrate the strain to the base and the strain distribution area.The existence of base shrinkage structure can further improve the strain extreme value on the basis of reducing the strain distribution area.According to the stability theory of the pressure bar,the structure of the bionic sensing element is optimized.Finally,based on the theoretical model and mechanical properties of the bionic sensing element imitating hair sensilla,a simple and efficient sensor element of cantilever beam imitating hair sensilla has been designed and fabricated.Its sensitivity,hysteresis,time response,frequency response and fatigue resistance were tested.On this basis,the application test of the sensor element is carried out to detect load,air flow and vibration signals.And a simple control circuit is designed to connect it and LED lights,which served as a signal indicator,sense the state of the surrounding environment.