| Sensors play an important role in the field of modern science and technology.It has the function of converting and quantifying various detection information into recognizable signals.Compared with traditional rigid sensors,flexible sensors have shown broader application prospects due to their excellent flexibility and bendability.The flexible pressure sensor can transform the detected pressure signal into an electrical signal,which is not only the core component of electronic skin but also plays an important role in the field of human-computer interaction and wearable devices.In practical,array sensor technology is the key to large-area pressure monitoring.By arranging multiple pressure sensors,not only the pressure can be measured,but also the position of the pressure can be accurately located.This pressure-position monitoring technology significantly improves the richness of pressure information obtained by the system.The performance of the array is closely related to the performance of a single sensor.Therefore,improving the performance of the pressure sensor can optimize the performance of the array.However,sensor arrays still have challenges in terms of energy consumption,detection of blind spots,and signal processing.With the increase in the number of sensors,energy consumption increases,and the operating cost and environmental burden of the system increase.The distance between sensors leads to blind spots in pressure monitoring,which limits the sensing ability of the system in some critical areas.The number of the sensors and the mutual influence between sensors also increases the difficulty of information processing and reduces the practicability of sensors.To overcome these challenges,it is necessary to develop high-performance bionic pressure-position pressure sensors,which will be the key to promoting the further development of sensor technology.As a typical arthropod,the scorpion gradually lost its visual ability during the 430 million years of evolution,but it has evolved excellent epidermal receptors.It shows that a scorpion’s slit sensillum can sense the vibration of a grain of sand within 20 cm,and even detect the vibration stimulus with a tarsal amplitude of 1 nm,which has an extremely sensitive sensing ability.However,only hypersensitivity is not enough to cope with the complex and changeable living environment,because enemies/prey can appear in any direction at any time in the natural environment.The angle between the metatarsal and the tarsal always changes when the scorpion is walking or stationary.Therefore,when the vibration signal is transmitted to the slit sensillum,the angle is not fixed.This requires a single slit sensillum that can not only respond to the pressure signal transmitted by the tarsal bone but also determine the position of pressure in different states.This indicates that a single slit sensillum can pressure-position sensing（both the magnitude and position of pressure）.This unique perception mechanism of the scorpion provides a valuable natural template for the design of new bionic pressure sensors.In this paper,the Heterometrius petersii,the Parabothus transvaalicus,and the Leiurus quinquestriatus are selected as the study object.The morphological characteristics of scorpion slit sensillum were observed.It is found that although the number of slits of the slit sensillum in different living environments is different,the basic morphology of the slit is consistent.Biobehavioral experiments were carried out and found that the state of slit receptors is changing all the time,which is the prerequisite for the pressure-position perception of slit sensillums.During the dynamic response analysis of the slit sensillum,it is found that the displacement change of the slit is the result of the joint influence of the pressure magnitude and position,and the single slit sensillum can perceive the pressure-position.Therefore,three biological models are established and finite element analysis is carried out to explore the functional mechanism of pressure-position of slit sensillum.It is found that scorpions perceive the magnitude of pressure through the deformation of slit units,and perceive the position of pressure through the deformation differences of each slit unit.That is,through the synergistic effect of various curved structural units of slit sensillum,pressure-position sensing is achieved.Subsequently,a bionic self-powered pressure sensor with an embedded crack structure and a self-powered pressure-position array is designed and fabricated.Based on the structural characteristics of the scorpion slit sensillum:first,the micro-scale slit is designed as a macro-scale embedded structure.Secondly,a bionic groove structure is introduced into the positive and negative friction layers using laser etching and reverse molding methods.The positive and negative friction layers with embedded structures effectively increase the actual area,greatly improving the signal output ability of the bionic pressure sensor.The performance of the sensor was characterized,and the sensor has high sensitivity（193 mV/kPa）and good stability（>13000）.Meanwhile,the magnitude and position of the pressure can be determined based on the output signal of the sensing array and the position of the sensor that changes the signal.In addition,the sensor-array also has the characteristic of self-powered,without worrying about energy consumption,and can achieve real-time/long-term pressure-position monitoring.It has potential applications in pressure monitoring,position positioning,path tracking,and other fields.Then,a bionic pressure-position pressure sensor based on the annular crack structure is designed and fabricated inspired by the scorpion pressure-position sensing mechanism.It can locate the area where the pressure is located（divided into 15 working areas）.A circular crack structure is introduced in the conductive layer to ensure that the conductive layer can sense the pressure in various areas,avoiding blind spots in detection.By characterizing the surface morphology and working process of the sensor,the mechanism of action of the bionic pressure sensor is explained.At the same time,the sensor exhibits high sensitivity(4.25 kPa-1),fast response（125 ms）,and good stability（>14000）.Moreover,due to the absence of detection blind spots and excellent pressure-position sensing performance of bionic pressure sensors,combined with the constructed signal acquisition and processing device,the potential application of sensors in the field of precision control was explored by using them as input devices.Finally,inspired by the hypersensitivity mechanism of scorpions and the layered structure of the skin,a bionic pressure-position pressure sensor based on a parallel crack structure is prepared by using a combinatorial bionic strategy.The bionic pressure sensor can achieve pressure-position sensing through signal changes in only two functional layers（two conductive layers）,without the need for complex signal separation algorithms and extensive calculations.The signal processing is simple and can be applied to various application fields.Based on the synchronization of the signal,the sensor can effectively identify the type of signal.The results of the application show that the sensor can detect the pressure caused by different forms of substances very well,regardless of whether the pressure is passively detected or actively applied.At the same time,it can be used to monitor the operating road conditions of lunar rovers or cars in an invisible environment.When the bionic pressure sensor is used for electronic skin,it can not only act as a pressure sensor（which can distinguish between contact force and sliding force,and identify pressure and strain signals）but also realize simple emotional communication.It has broad application prospects in the fields of electronic skin,human-computer interaction,and so on.In summary,the manuscript takes scorpions as biological prototypes and uses bionic ideas and methods to study the surface morphology and stimulus-response characteristics of scorpion slit sensillum in different habitats.Based on the perceptual structural characteristics of the slit sensillum,a bionic visualization model of the slit sensillum perceptual structure is established.By combining theoretical models with numerical simulations,the mechanism of the pressure-position sensing function of the scorpion slit sensillum is revealed.Based on this,three bionic pressure-position sensing pressure sensors are developed to overcome the shortcomings of flexible pressure sensors in pressure-position sensing.The synchronous sensing of pressure magnitude and position is achieved,and the basic performance and application characterization of the sensing elements were completed. |
