Research On Force Sensor Based On Pressure Sensitive Conductive Silicone Rubber

With the booming of intelligent robot technology,tactile sensors has been widely used in robots.The development of flexible tactile sensor that can simulate the human perception is the key to achieving intelligent robots.The robot interacts with the surrounding environment through the tactile sensor wrapped on its surface to obtains information that is in contact with the outside world to guarantee the security of the interaction.The tactile sensor should be flexible to cover the surface of robots.As a new functional material,the pressure-sensitive conductive polymer material has properties of excellent flexibility,conductivity and piezoresistivity.Therefore,it is the ideal material for perceptual element of tactile sensors.The pressure-sensitive conductive silicone rubber,a kind of composite polymer functional material,is composed of silicon-oxygen bonds(Si-O).It is a linear high-elastic polymer material.As core sensitive element of tactile sensors,the properties of the material directly affect the performance of the sensor.This subject roots in the National Natural Science Foundation of China:Flexible surface electric field tactile sensor with both contact position and pressure detection function(NO.51575111).Based on the piezoresistivity characteristics of conductive rubber,a non-arrayed flexible tactile sensor with force detection function was designed and fabricated.First,in order to study the influence of the type and content of conductive fillers on the conductivity and piezoresistivity characteristics of pressure-sensitive conductive silicone rubber,choose the appropriate polymer binder GD414 room temperature vulcanized silicone rubber and acetylene black,graphite,nickel powder,copper powder,etc.A variety of conductive fillers and other additives to determine the preparation process of pressure-sensitive conductive silicone rubber.The conductive properties and piezoresistivity properties of pressure-sensitive conductive silicone rubber filled with conductive fillers of different types and contents were analyzed.On this basis,in order to improve conductivity and piezoresisitvity of pressure-sensitive conductive silicone rubber.The joint application of carbon-based and metal-based conductive fillers on it was explored.And the modified effect of it on Pressure-sensitive conductive silicone rubber was investigated.In the investigation,two-phase seepage flow phenomenon,which different from the phenomenon when single fill was used,appeared and its significance was explained.In addition,the reinforcement mechanism of nanomaterials was analyzed,And the effect of different content nanomaterials on performance of Pressure-sensitive conductive silicone rubber such as conductivity,piezoresisitvity,repeatability,hysteresis and creep properties was investigated through experiment.The experiment result showed the improving effect of nanomaterials on Mechanical properties of polymer materials.Then the pressure-sensitive conductive silicone rubber sample was manufactured after optimized material combination selection.On this basis,a sensor sample with a five-layer structure was designed.A nonlinear piezoresistivity model was fitted based on the piezoresistivity characteristic data,and a compensation function was added to keep a linear relationship between input and output.Finally,the feasibility of the tactile sensor was verified through the performance analysis of detection error and dynamic characteristics.