Research On Characteristics Of Optical Reflective High-resolution Tactile And Slip Sensing

As an important part of the robot’s basic perception ability,tactile and sliding measurement plays an important role in improving robot’s ability of sensing the environment and forming a closed-loop control.With the expansion of the application field of robots,sensors are required to work in complex environments.Various requirements such as surface compliance,electromagnetic compatibility,flexibility,quantitative measurement capabilities,and high resolution are put forward for the sensors.However,highly integrated and arrayed electrical tactile sensors are difficult and costly to achieve.Optical tactile sensors with flexible characteristics are not ideal for the quantitative measurement of three-dimensional force and the slip perceiving.In this context,this paper proposes a tactile slip sensor based on light reflection imaging,which realizes the quantitative measurement of three-dimensional mechanical information,the measurement of slip information and the sliding predicting when the sensor is in contact with the measured object.1.The bump mechanics model of the sensing principle is analyzed,and the forcelight conversion geometric model of the bump is calculated,and the principle of quantitative measurement of the normal force and tangential force of the bump structure is demonstrated.The comparing demonstration of the sliding measurement of the equalheight bump array and the unequal-height bump array are carried out.2.Through the ABAQUS finite element analysis software,the stress and strain analysis of the deformation caused by the bump on the gel surface was carried out,and the feasibility of the proposed sensing method was verified.Further,the finite element analysis of the various array arrangements of the bumps is further carried out,and the influence of the arrangement method on the sensing performance is explored.The sensor design is further optimized based on the simulation conclusion,manufacture process,image quality and other aspects.An image processing algorithm is designed to extract the image feature values related to the normal force and the tangential force in the image.3.The optical reflective tactile slip sensor is manufactured.Based on the prepared tactile sensor design,a calibration system for normal force and tangential force is built,and the large bump,small bump and the optimized array bump are obtained by simulation.The structure has been calibrated experiments,and the calibration curves of normal force and tangential force are obtained.According to the calibration curve and imaging theory,the sensor resolution is theoretically analyzed,and the actual resolution of the system is verified through experiments to meet the theoretical resolution.The sliding experiment and the grasping experiment verify the sensing and prediction effect of the sensor system designed in this paper on sliding sensation.The theoretical model of the proposed sensor is verified through the research in this article.The arrayed sensor has a normal force measurement range of 1～15N,and the normal and tangential resolution reach the order of 10 m N.The relative uncertainty in the normal force measurement is under 5.77%,the relative uncertainty in the tangential force measurement is under 7.54%.