Structure Design And Characteristics Research Of Capacitive Flexible Tactile Sensor

Tactile perception,as one of the basic perception abilities of robots,has always been the focus of attention in the field of robotics.With the rapid development of robotic technology,a variety of tactile sensors with different sensing mechanisms have emerged.Among them,capacitive tactile sensors have been adopted by many researchers due to their advantages such as high sensitivity,fast response speed and wide dynamic range.In order to improve the initial capacitance and sensitivity of the capacitive tactile sensor with the structure of coplanar electrodes,a flexible capacitive three-dimensional force tactile sensor with multi-interdigital electrodes is proposed in this paper.In order to design a capacitive tactile sensor with superior performance,the capacitance model of the coplanar electrodes was analyzed and the tactile sensing unit with coplanar interdigital electrodes was designed.The influence factors of output capacitance of the sensor with coplanar interdigital electrodes were analyzed theoretically,which lays a foundation for design of sensor structure.The tactile sensing unit with the coplanar interdigital electrodes and the tactile sensing unit with the coplanar double electrodes were designed and analyzed by simulation.The simulation results showed that the tactile sensor with the coplanar inerdigital electrodes had the characteristics of larger initial capacitance and higher sensitivity.The finite element simulation of the electric field distribution of the coplanar interdigital electrodes and the coplanar double electrodes was carried out,and the reason for the superior performance of the tactile sensing unit with the coplanar interdigital electrodes was explained.Based on the coplanar multi-interdigital electrodes,the structure design of the three-dimensional force tactile sensor was carried out.The finite element simulation of the designed sensor was carried out,and the capacitance output characteristics under different forces were obtained.The designed sensor was fabricated,the experimental calibration platform was built,and the three-dimensional force calibration of the sensor was completed.Using the experimental calibration data,the three-dimensional force decoupling of the sensor was realized by using BP neural network.The results show that the sensor not only has good flexibility,but also can realize three-dimensional force detection in 0-10 N.In order to further improve the initial capacitance and sensitivity of the sensor and optimize the output characteristics,the electrode layer optimization and dielectric layer optimization were carried out for the three-dimensional force tactile sensor with the coplanar interdigital electrodes.In the aspect of electrode layer optimization,the structure of serpentine interdigital electrodes,the structure of spiral interdigital electrodes and the structure of interdigital electrodes with branches were proposed.It was verified by finite element simulation that all three electrode structures could improve the initial capacitance and sensitivity of the sensor to some extent.In terms of dielectric layer optimization,the dielectric layer with inverted pyramid array and the dielectric layer with inverted cone array were proposed.It was verified by finite element simulation that both of them could improve the linearity of capacitance output curve of the sensor.The work of this paper aims to break the parallel electrode structure of traditional capacitive tactile sensor,design a new type of capacitive tactile sensor with the coplanar interdigital electrodes,and analyze its output characteristics,so as to provide reference for the development of capacitive tactile sensor with excellent performance.