Interface Microstructure Design Of 3D Printing Highly Sensitive Pressure Sensor

Electronic skin,as a form of artificial intelligence skin,has emerged as a cutting-edge research topic,enabling robots and prosthetics to possess the ability to sense and measure physiological signals of the human body.Among its various functions,pressure perception stands as the fundamental capability of electronic skin,and enhancing its pressure perception ability holds immense significance.Sensitivity serves as a pivotal performance parameter for pressure sensors integrated within electronic skin.Particularly,when detecting delicate signals like heartbeat and pulse,pressure sensors require high sensitivity to ensure accurate sensing.However,the current sensitivity levels of pressure sensors are not satisfactory,necessitating the need for improvement.One of the primary approaches to enhance sensitivity involves the construction of microstructures on the surface and potentially within the sensitive dielectric layer.Among these approaches,the construction of surface microstructures stands out as the simplest and most effective method.Common types of surface microstructures encompass microcone structures,microcilia structures,microdome structures,microcolumn structures,and microridge structures.To address this challenge,the thesis investigates the use of microstructures on the surface of the sensitive dielectric layer of the pressure sensor.Nine different surface microstructures were selected for analysis,including cylinder,cone,pyramid,dome,cuboid,long micro-ridge ladder,cuboid ladder,long micro-ridge,and cylinder ladder.Through simulations conducted using COMSOL Multiphysics,the sensitivities of each microstructure has been determined.The findings revealed that the cylindrical ladder structure exhibited the highest sensitivity among the tested microstructures.Subsequently,we focused on the cylindrical ladder structure and examined the relationship between various structural parameters of the first layer,including diameter,layer thickness,layer number,separation distance,and step width,with the sensitivity of the sensor.The study revealed that the sensitivity of the flexible sensor decreased with increasing diameter of the first layer,while it increased with greater layer thickness,number of layers,separation distance,and step width.Finally,we successfully utilized 3D printing technology to fabricate flexible capacitive pressure sensors with different surface microstructures.The simulation results were then validated through electromechanical performance characterization.The flexible capacitive sensor with a cylindrical ladder structure exhibited a sensitivity of 0.12 k Pa^-1 within the range of 0-2 k Pa.It demonstrated a response time of approximately 21 ms,a detection limit of 20 Pa,and a hysteresis of 12.567%.Moreover,the sensor showcased excellent electromechanical performance and was successfully employed in a demonstration application for rainfall monitoring and electronic skin.