Design And Force Prediction Of Tactile Sensor Based On Piezoelectric Effect

With the rapid development of intelligent robots,tactile sensors have attracted great attention from many researchers.Piezoelectric tactile sensors based on the piezoelectric effect are widely used due to their simple structure,low power consumption,durability,high sensitivity,and good reliability.For the piezoelectric tactile sensor,the choice of piezoelectric material has a greater impact on its performance;the analysis and prediction of the force loaded on the sensor surface helps to improve the intelligence of the tactile sensor.With the rapid development of sensing technology and material science,the design of piezoelectric tactile sensors with high sensitivity and accurate force prediction is crucial to the intelligentization of robots.In order to improve the intelligence of piezoelectric tactile sensors,this paper uses the finite element simulation software COMSOL Multiphysics to study the performance differences and influences of different piezoelectric materials on the basis of fully studying the sensing mechanism and commonly used materials of piezoelectric tactile sensors.The influence of performance factors and piezoelectric layer structure optimization on performance.On this basis,two different neural network algorithms are used to predict the force.The main research contents are as follows:(1)Material selection of piezoelectric tactile sensor.In the selection of materials for each part of the sensor,copper(Cu)and polydimethylsiloxane(PDMS)were selected for the electrode layer and surface protection layer,respectively.The alternative materials for piezoelectric materials are lithium niobate(Li Nb O₃),Piezoelectric ceramics(PZT)and polyvinylidene fluoride(PVDF).Combine the above materials to obtain three tactile sensors with the same structure and different piezoelectric materials,and then use COMSOL to apply normal force per unit area to the sensor to detect the average potential of the piezoelectric layer surface,the total displacement of the piezoelectric layer surface and the piezoelectric layer Displacement of the center point of the surface.The experimental results show that among the three piezoelectric layer materials tested,PVDF has the best piezoelectric performance.The experiment and analysis in this article are based on the design and research of piezoelectric tactile sensor based on PVDF as the piezoelectric layer material.(2)Study the factors that affect the performance of piezoelectric tactile sensors.On the basis of full analysis and comparison,the structure of the piezoelectric tactile sensor and the materials of each component are determined.At the same time,the influence of the thickness of the protective layer on the surface of the sensor and the inclination angle on its sensitivity is deeply studied.The experimental results show that the sensitivity of the sensor becomes larger as the thickness of the surface protective layer becomes thinner,and becomes smaller as the tilt angle increases.Afterwards,the following simulation experiments are carried out respectively:small objects of different materials slide on the surface of the sensor,and objects of the same material slide on the surface of the sensor with different friction coefficients;for the above experiments,by detecting the potential change of the piezoelectric layer of the sensor,the sensitivity of the sensor is reflected.The effect of touching objects.Experimental results show that the piezoelectric tactile sensor model designed in this paper can accurately detect the roughness of the surface of the sliding object while identifying the material of the sliding object.Finally,the structure of the piezoelectric layer of the sensor was optimized,and a series of simulation experiments were carried out.The results show that the piezoelectric sensor using a cylinder array for the piezoelectric layer has a higher sensitivity,and within a certain range,the sensor sensitivity increases with the increase of the radius of the cylinder bottom surface.(3)Research the force prediction of piezoelectric tactile sensor based on neural network algorithm.Different from the traditional sensor force prediction research that applies a tangential force or a normal force perpendicular to the sensor surface,this paper uses finite element analysis technology to apply different directions and different magnitudes of force to the tactile sensor,and calculates the potential change of the piezoelectric layer of the sensor.data.On this basis,the radial basis function(RBF)neural network algorithm and the BP neural network algorithm are used to analyze and predict the size and angle of the force applied to the sensor surface,and predict the mapping relationship between the sensor potential and force.The research results show that the RBF neural network algorithm can be well applied to the force prediction of the piezoelectric tactile sensor.The research work in this paper has accumulated rich experience and laid a certain theoretical foundation for the further exploration of piezoelectric tactile sensor material selection,the research of factors affecting sensor sensitivity,and the optimization of piezoelectric layer structure.At the same time,it also provides a solid theoretical foundation and technology accumulation for the force prediction of the tactile sensor.