Research On Multi-parameter Perception Of Flexible Finger Based On Fiber Bragg Grating

The particularity of soft robot in structure and material makes it have certain flexibility and compliance.It can realize bending,torsion,stretching and other actions,and has certain continuity and good interaction in operation,which significantly improves the adaptability and safety of the robot in work.The research on multi parameter tactile sensing of flexible fingers is of great significance to the development of flexible manipulators.The main contents of this paper are as follows1)The research status of flexible manipulator at home and abroad is compared,including material structure,driving mode,with emphasis on sensing scheme.Fiber Bragg grating(FBG)is proposed to be used in flexible hand sensing system.FBG has the advantages of small volume,light weight,high sensitivity,anti electromagnetic interference,reusability and so on,and becomes the basic element of our sensing system.2)The basic principle of fiber Bragg grating(FBG)is introduced,including the structure and fabrication method of FBG,the principle of strain and temperature measurement,and the multiplexing technology of FBG sensor.Finally,the key factors of FBG measurement are introduced.The introduction of FBG in this chapter provides a theoretical basis for sensor sensing in the following research.3)A pneumatic finger is designed by structural simulation and finite element analysis,and the real object is made by 3D printing and silica gel casting.The bending property is improved by adding high tensile fiber.4)The sensor system of the flexible finger is built based on pressure detection and bending detection.The fingertip position,deflection angle and bending angle were analyzed.A contact detection method based on gradient descent is proposed.The method starts from the original data,which is low-cost,accurate and reliable.It provides guidance for the manipulation of flexible fingers,avoids the delay and uncertainty of grasping or releasing,and is conducive to the analysis of grasping stability.A folded sensor which can change the sensing state by adjusting the shape is designed.The shape of the folded surface is used to change the attitude of the embedded sensing element(FBG),and then the sensing characteristic(sensitivity)of the sensing element is changed.The rolling detection is carried out to preliminarily verify this point.5)In order to solve the shortage of pressure detection ability,a new type of hierarchical detection sensor is designed,which provides a new and comprehensive detection scheme for the flexible manipulator sensing system.This design is of great significance for the research of robot fingers and artificial skin,and realizes the force sensing ability in complex contact environment.Finally,it summarizes the work of the whole subject,puts forward the innovation points and the shortcomings of the current research,puts forward the areas that need to be improved,and forecasts the future work.