Design and Sensitivity Analysis of Flexible Pressure Sensor for Guidewire Tip
To detect the contact force between the guide wire tip and the blood vessel wall during vascular inter-ventional surgery,a piezoresistive flexible pressure sensor is developed by analyzing the sensing mechanism of conductive composite polymer materials.Carboxylated single-walled carbon nanotubes(COOH-SWCNTs)are utilized as conductive fillers.The sensor is installed on the guide wire tip,which has an outer diameter of 1.8 mm and a length of 5 mm.The sensor is characterized by its small size and high sensitivity.The sensitivity simulation model of piezoresistance is established by finite element method;An experimental platform is built to test the sensitivity curve and calibrate the sensor;A phantom model of the vascular interventional procedure is established,and the contact force between the tip and the vascular wall is measured.The simulation and experi-mental results show that the sensitivity of the flexible pressure sensor is 2.05 × 104Ω/N and the measuring range is 1 N.During the process of guiding wire intervention into blood vessels,the maximum contact force between the tip of the guiding wire and the blood vessel wall does not exceed 0.5 N.The sensor can effectively detect the dynamic contact between the tip of the guide wire and the vascular wall during vascular intervention,offering a new method for force feedback control in vascular intervention surgical robot.
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