Design And Analysis Of Wrist And Hand Composite Humanoid Dexterous Hand

The dexterous hand is a kind of robot that imitates the physiological structure of human hand.It can grasp and operate non-standard objects in a certain space by working together with the robot arm or other robots.With the advancement of industrialization,the application of dexterous hand has become more and more extensive,meanwhile,the dexterous hand has higher standards for its flexibility and structural robustness.In this thesis,based on the physiological and anatomical analysis of the human hand,a hybrid humanoid dexterous hand was developed and designed.On the hand and wrist,based on the improved D-H parameter method,kinematics analysis was accomplished.The algorithm verification,hand and wrist workspace simulation and strength and stiffness check of key components were completed.Finally,the flexibility and structural robustness of the dexterous hand were checked on by experiments.As follows,specific research contents are listed:1.Structure design of dexterous hand.By analyzing the physiological and anatomical structure of the human hand and wrist,the design index of the dexterous hand was obtained.On the basis of the physiological characteristics of the human hand,a finger transmission mechanism based on the tendon rope of the rolling joint was proposed,and a tendon decoupling mechanism was introduced into the palm.A 2-P5R+ inverse parallel four-link composite wrist mechanism was developed according to the human wrist action and driving characteristics Then the design of the main mechanical structure of the dexterous hand is realized.2.Finger kinematics solution of dexterous hand.Equivalent modeling of connecting rod was carried out on the finger and the improved D-H parameter method was applied to construct the system to obtain the forward kinematics equation of the finger.The joint transformation matrix was moved to the tangency point and equivalent connection point of the driving tendon rope through the position vector,and the mapping relationship between the finger joint Angle and the total retraction length of the tendon rope was obtained through the position vector between the two points,so as to realize the overall kinematics of the finger.The problem that the kinematics of the non-pulley guide rope drive mechanism is difficult to solve due to the complicated geometric relationship is solved.3.Kinematics solution of dexterous hand.The wrist composite mechanism was disintegrated into the wrist flip mechanism + two P5 R mechanisms.And the inverse parallel four-link linkage part of the wrist flip mechanism was decouples through the relationship between the position vector and the length of the connecting link to obtain the end kinematic equation.Then the base coordinate system of the wrist flip mechanism was transformed to coincide with the base coordinate system of the P5 R mechanism on both sides.The input displacements of P5 R mechanisms on both sides were inversely solved by the end pose of the wrist flip mechanism to realize the kinematics solution of the wrist composite mechanism.This thesis solves the problem that the motion mapping relationship between the master and slave ends of the double-branch chain mechanism with high coupling relationship is not clear.4.Strength and stiffness of dexterous hand and multi-rigid body simulation analysis.Strength and stiffness analysis of key components of hand and wrist was carried out using workbench based on finite element method.The work space point cloud of fingers was obtained by MATLAB robot toolbox,and the Adams equivalent simulation results were compared with the deduced results of finger joint Angle-driving tendon and rope mapping,which verified the correctness of the finger solution idea.The results of Adams simulation were compared with the results of decoupling and kinematics of wrist flip mechanism,and the correctness of the solution method was verified.The wrist-working space was obtained by Adams simulation model.5.Conduct a real dexterous hand experiment.The effectiveness of dexterous hand DOF was verified by various gestures.The grasping stability of dexterous hand was verified by grasping various types of working objects.The dexterity of dexterous hand was verified by manipulating the daily alien objects.The average fingertip output force of each finger was obtained by reading the peak fingertip output force of the five fingers of dexterous hand several times.Output with the same input were recorded multiple times before and after the dextrous hand was affected by the external impact to analyze and verify the impact robustness of the five fingers of the dextrous hand.