Design And Implementation Of Multifunctional Pneumatic Soft Gripper

Compared with traditional rigid manipulators,soft grippers have the advantages of high compliance,more degrees of freedom,and strong adaptability to various shapes and objects,and are widely used in fruit and vegetable picking,industrial production,deep-sea sampling,elderly care and disability assistance and other fields.At present,the soft gripper developed in China still has the problems of single function,poor load capacity,and insufficient adaptability to flat objects;In order to solve the above problems and improve the grasping ability of the soft gripper,this thesis proposes to design a multi-functional pneumatic soft gripper with fingertip gripping function,envelope grasping function,bending hooking function and fingertip adsorption function.The main research contents of the thesis are as follows:(1)According to the target object of soft gripper,with reference to the physiological structure and bending mechanism of human fingers,a multi-functional pneumatic soft gripper is proposed.Determine the structural scheme of the finger root driver,fingertip driver and vacuum suction cup of the soft finger,it is best to determine the overall structure scheme of the soft gripper according to the work needs of the gripper.(2)Determine the silica gel with suitable hardness as the material for making the soft gripper,analyze the mechanical properties of the silica gel material,establish the second-order constitutive model of the material,and determine its mechanical property parameters.Through the principle of torque balance and the principle of virtual work,the static model of bending and deformation of soft fingers was established.Through the modeling idea of segmented constant curvature of flexible mechanism and combined with D-H coordinate method,the kinematic analysis of soft fingers was carried out to determine the relationship between its structural parameters and the end pose.(3)The influence of structural parameters such as cavity wall thickness,cavity spacing,number of cavities,strain limiting layer thickness and flexible steel plate thickness of fingertip and finger root driver on the bending performance of soft actuator was analyzed.By comparing the finite element analysis results,the optimal size parameters of the soft finger were obtained.Finally,through the finite element analysis of the bending deformation of soft fingers,the relationship between the bending deformation angle of the fingers and the driving air pressure was given.(4)Firstly,the multi-functional pneumatic soft gripper was prepared by silica gel pouring molding process,and an experimental test platform was built to determine the bending deformation characteristics of soft fingers and the relationship between the terminal output force and the driving air pressure.Then,the soft gripper was mounted on the robotic arm,and the maximum grasping diameter,maximum grasping quality,maximum hooking quality and maximum adsorption mass of the soft gripper were tested experimentally.Finally,through the experiment of grasping and applying the soft gripper,the results showed that the gripper has good adaptability to objects of various shapes and sizes.