Research On Preparation And Application Of Flexible Stress Sensor Based On Elastic Material

The flexible stress sensor is a new type of sensor.Compared with the traditional stress sensor,the flexible sensor has the advantages of good flexibility,free bending and folding,and flexible structural form.More and more researchers are committed to flexible sensors Research.In order to solve the problems of insufficient stretchability in the research of flexible sensors and complicated microstructure fabrication process,this topic proposes the combination of carbon nanotubes?CNTs?and Ecoflex silicone rubber to prepare an assembly of stretchable electrodes and composite dielectric layers The capacitive flexible stress sensor has designed a flexible sensor structure for three-dimensional force detection under the best parameters after the device performance test;at the same time,for the defect of the capacitive sensor's low tensile sensitivity,an innovative method is proposed Stretchable resistive strain sensor based on sandpaper microstructure.The main content and innovative results of this dissertation are as follows:1.Preparation and performance research of capacitive flexible stress sensor based on fold microstructure and composite dielectric layer.The carbon nanotube stretchable electrode is mainly prepared by the template transfer method,and the electrode wrinkle treatment is used as the upper and lower plates of the capacitive sensor.The composite dielectric layer with high dielectric constant is prepared by mixing carbon nanotubes?CNTs?with Ecoflex silicone rubber,and assembled with upper and lower electrodes to form a capacitive flexible pressure sensor.The test and analysis of the response performance of the device shows that the introduction of the pleated structure electrode and the composite dielectric layer significantly improves the pressure response performance of the sensor,and the maximum sensitivity under the pleated structure reaches 2.13 KPa^-1.At the same time,the sensor has minimal hysteresis effect and high response time?<100 ms?,good stability and repeatability,and has a large tensile performance,but its tensile sensitivity is poor?only 0.12?,uncomfortable Stress measurement at large deformation.2.Application research of capacitive tactile sensor based on three-dimensional force measurement.After analyzing the sensor performance of the pleated structure electrode and the composite dielectric layer,a flexible capacitive sensor structure for three-dimensional force measurement is designed,and its mechanical structure and working principle are analyzed in detail.The response performance test of the prepared three-dimensional force sensor shows that the prepared sensor has better response stability and repeatability,and the repeatability error is within 15%.In the sensitivity of three-dimensional force calibration,the sensitivity of the tangential force detection of 0⁰.8 N on the X and Y axes is 46.4%/N,52.7%/N,and the normal force detection of 0¹.2 N on the Z axis The sensitivity is 84.4%/N,and the relationship curve between k?d?-F is established to realize the discrimination of three-dimensional force.3.Preparation of stretchable resistance sensor based on sandpaper microstructure.Aiming at the defect that the prepared capacitive sensor has low sensitivity to tensile strain measurement,a stretchable resistive strain sensor was prepared by copying sandpaper patterned microstructure on the Ecoflex silicone rubber substrate and combining with the CNTs conductive layer.Tests have shown that the sensor device has excellent linearity in response to tensile stress,with a sensitivity of 2.7 at a tensile strain of 107%,which is more than twenty times that of a capacitive sensor;It has good repeatability under 3000 cycles of stretching.The sensor can be widely used for stress/strain measurement at large deformations such as finger joints and knee joints.