| Human skin is one of the most complex and fascinating organs.It possesses a network of highly sensitive tactile sensors that are able to convert mechanical stimuli into physiological signals,which are then interpreted by the brain.In recent years,tactile sensors have received widespread attention due to their potential applications in biomedical sensors,smart robots and bionic prostheses.Among them,three-dimensional force tactile sensors can distinguish between normal pressure,lateral strain,and bending and other multidimensional force field mechanical stimuli.Assist the intelligent robot to complete tasks such as distinguishing objects,grasping objects and determining textures.However,the existing tactile sensors output electrical signals through lead wires,which are susceptible to temperature drift and electromagnetic interference,and cannot achieve high-density arrays.Therefore,this article uses image information to complete the three-dimensional force perception of the tactile sensor,avoiding the interference introduced by complex circuits,and has important engineering application significance for realizing the miniaturization of the tactile sensor.Based on the analysis of tactile sensors with different working principles,this paper proposes a vision-based three-dimensional force high-density tactile sensor.The sensor consists of a micro-pillar array with temperature measurement coating and black coating,an image sensor and a white film.The sensitive element is a micro-pillar array with temperature measurement coating and black coating,with a high spatial resolution of 625 sensing points per square centimeter,which can realize high-resolution three-dimensional force field and temperature field sensing on the basis of flexibility.Use the deformation of the micro-pillar and the color of the thin-layer chromatography composite material to obtain the three-dimensional force and temperature distribution on the micropillar,and use the image edge detection-edge growth algorithm to process the micro-pillar deformation and bending images collected by the image sensor to calculate the expansion rate K And the relative offset L to achieve highresolution perception of the three-dimensional force field and temperature field.The finite element simulation experiment proves that the tactile sensor proposed in this paper has no three-dimensional force coupling,and the optimal parameters of the sensor are determined.The performance test of the tactile sensor shows that the pressure sensitivity of the sensor is 0.063 mN-1,and the shear sensitivity is 0.102 mN-1.It has high sensitivity,high linearity,excellent stability and heat resistance,and no zero point drift.Application experiments have proved that the tactile sensor can sense the basic characteristics of the object’s shape,texture,adhesion,hardness,weight and temperature,simulate human hands to test the pulse,distinguish between true and false fruits,sense the weight of water cups,and identify different objects.There are broad application prospects in future intelligent systems. |
