Mechanism And Bionic Research Of Ultrasensitive Micro-Vibrational Sensilla Of Scorpion

Sensors which regarded as the basis and core of intelligent manufacturing are the source of information acquisition.Among various types of sensors,mechanosensor is a kind of sensor that can transform mechanical signal(sound,pressure,vibration,acceleration,etc.)into electrical signal.Because mechanical signal which contains many characteristic parameters of equipment and living organisms is continuously generated in the process of running,mechanosensors is one of the most widely used sensors in the field of engineering.In order to satify the upgrading demand of Chinese manufacturing,it is urgent to achieve the transformation of mechanosensors from traditional to new type.Therefore,the invention of new type of mechanosensor with excellent comprehensive performance has become a common technical problem in various key areas.In order to survive and reproduce in the cruel environment,organisms have evolved ultrasensitive mechanoreceptors on their body surface,which can accurately identify and locate weak mechanial signals such as air disturbance and ground vibration from complex noise environment.Hence,the mechanoreceptors provide a natural model for the invention of mechanosensors with excellent comprehensive performance.Among many kinds of mechanoreceptors,the micro-vibration sensillum on the walking legs of scorpion not only can detect and locate the micro-vibrational signal caused by a sand particle within 20 cm of the soil surface having high attenuation factor,but also detect the micro-vibration caused by insect activity in the underground cave around 50 cm.Therefore,the study on the ultrasensitive mechanism of vibration sensillum and themanufacture of bio-inspired mechanosensor will provide new way for the development of mechanosensor with excellent performance which is needed in key fields.In this paper,scorpion Heteroremtrus petersii was selected as the biological template.The main contents of this paper are as follows:Firstly,the distribution,functional unit composition and perception process of micro-vibration sensilla were deeply studied,and then the multi-scale structural characteristic parameters,material composition and material mechanical properties under different physiological conditions were analyzed.The above research lays a foundation for revealing the functional mechanism of micro-vibration sensilla.Secondly,the coupling sites between mechanosensory neurons and slit unit were studied,which indicate that receptive field of mechanosensory neuron located in the vicinity of each slit tip.Based on the results of experiment and theory analysis,we find that scorpion can effectively collect the tiny mechanical signl through utilizing the energy concentration effect of the near-tip stress field at the slit tip,and then convert the mechanical signal into electrical signl through using the mechanosensory neuron.Nextly,the test platform of bioelectric response about micro-vibrational sensilla was built,and the frequency response characteristics of bioelectric signal produced by micro-vibration sensilla were analyzed.The results indicate that the bioelectrical signals produced by the mechanosensory neurons have significant frequency selectivity and are extremely sensitive to the vibration signals at 55 Hz.Based on the the distribution and stress characteristics of the micro-vibrational sensilla,it is found that the peak value of the bioelectric signals is caused by the large extrusion deformation of the micro-vibration sensors at 55 Hz.It is concluded that the micro-vibrational sensilla achieve efficient screening of mechanical signals in complex noise environment through using the resonance effect.Nextly,the structural safety of the micro-vibration sensilla is analyzed.It is found that the main body of the micro-vibration sensor is composed of multi-scale layered structure and resilin with anti-fatigue property.The synergistic effect of this materialand structure gives the main body excellent anti-fatigue fracture performance.Based on the mechanical properties of the epicuticle and the cuticular membrant covering the slit and the microstructural parameters of the vibrational sensilla,the relationship between the composite modulus and the applied load was established.The theoretical analysis shows that the cuticular memmbrane covering the slit tip can effectively prevent the initiation of new cracks from the slit tip through the reasonable elastic modulus configuration.Meanwhile,the balance mechanism of sensitivity and structural safety about slit unit is further analyzed through establishing the relationship between the composite modulus of micro-vibrational sensilla and width of slit.The theoretical analysis indicates that,in order to amplify the signal at the near-tip stress field,the cuticular membrane with low bending stiffness makes the crack-shaped slit deform easily under weak mechanical signal.In contrast,when the mechanical energy is so high that makes the crack-shaped slit extend and propagate similar to a pre-existing crack,the cuticle membrane absorbs deformation energy and inhibits the slit excessive opening by regulating composite elastic modulus.Finally,the bionic models of mechanosensors based on the structural characteristic and functional mechanism are established,respectively.Based on the above two models,bionic design and manufacture of mechanosensor are carried out,respectively.The results indicate that both of this two modle can significantly improve the sensitivity of mechanosensor.