Research On Pressure Sensors Based On Conductive Rubber

Flexible pressure sensor has the characteristics of flexibility,extension,free bending and folding,portable,wearable etc.,which is widely applied in electronic skin,health care,electron and elect,sports equipment,textile,aerospace,environmental monitoring and other fields.Because the resistivity of conductive rubber is related to external forces and can be used as a flexible sensor material,the conductive properties of carbon black have lasting stability.The conductive properties of the material can be adjusted and has good reinforcing effect on the matrix material.Using silicone rubber as matrix prepared by the addition of carbon black filled conductive polymer composite material has good pressure resistance,which is very valuable in the field of flexible sensing technology.In this paper,based on the conductive mechanism of conductive rubber polymer composites,the surface oxidation pretreatment of filled carbon black was carried out,could improve the dispersion in the conductive rubber,and conductive rubber samples with excellent properties were prepared.The static and dynamic characteristic of conductive rubber were researched,which analyze the performance indexes of the measuring range,sensitivity,hysteresis under different conditions,and unit step response performance parameters and frequency characteristics.A new type of flexible array type plane pressure detection system has been designed,which has initially realized plane stress measurement and imaging display.In order to obtain the stable performance of the pressure resistance and sensing performance,and better suitability for the flexible pressure sensor of the conductive rubber,the experimental scheme,the experimental material and the preparation process are determined.The gas phase and liquid phase method respectively applied on carbon black surface by oxidation pretreatment,and conductive rubber filled acetylene carbon black with excellent pressure resistance properties was prepared,the pressure resistance characteristics of conductive rubber filled with carbon black filled with different pretreatment methods were analyzed.The research found that conductive rubber filled acetylene carbon black content 6%by gas phase oxidation pretreatment can be treated as flexible sensor sensitive material.when carbon black surface modified by O2 oxidation at 200? for 60 minutes,the content of hydroxyl and carboxyl group is high,the distribution of the silicone rubber is uniform,and the conductive rubber resistance is reduced by 1 orders of magnitude,it shows good pressure resistance characteristics.Study on the static characteristic of conductive rubber pressure sensor,the static performance are expounded including measuring range,linearity,sensitivity and hysteresis,calculation of characteristic parameters and curve fitting based on MATLAB.By measuring the piezo resistive properties of conductive rubber with different thickness,it is found that the measuring range of conductive rubber increases with the increase of thickness,and the sensitivity decreases with the increase of input pressure.The measuring range of the conductive rubber with thickness of 4mm is determined that is 0.1-10N,linearity error is 0.05%,hysteresis is 0.69,the static characteristics of conductive rubber produced by this formula is the most appropriate flexible substrate as the conductive rubber pressure sensor.Study on the dynamic characteristic of conductive rubber pressure sensor,build analysis test system based on LMS test Lab,complete the configuration of hammer system and excitation system,carry out the dynamic characteristic test of conductive rubber,and analyze the test data have shown that the response time of the conductive rubber sample less than 1ms and stability time within one second under hammer excitation step.It shows that the conductive rubber as flexible pressure sensor which has a good step response characteristic.In the frequency response test of the vibration system,the natural frequency increases with the increase of the thickness of conductive rubber.Based on the study of the properties of conductive rubber,the optimal sensitive element material is selected,a new type of conductive rubber array type pressure sensor has been designed through the development of the hardware and the software an array type pressure distribution detection system is designed,which is the 16x16 array unit to realize the plane stress distribution of real-time data acquisition.Through applying different shapes of objects,the collected data were visual imaging processing,a relatively high resolution image was got,and the plane stress distribution and imaging display was realized.