Research On The Design Method Of An Underactuated Robotic Dexterous Hand

Since the emergence of human beings,flexible wrist and dexterous hands have played an extremely important role in the production and life of human beings.The strong dexterity of human hands is the result of mutual cooperation between the wrist and hands.Around the world,millions of people with hand amputations are suffering from the loss of their ability to live normally.Therefore,how to design a humanoid robotic dexterous hand that can be used by amputees is a hot topic of research at home and abroad.However,the existing dexterous hand still have the following three problems:(1)the structure and control system of the prosthetic hand is complex,the volume and mass are too large;(2)the grasping movement of the prosthetic hand is not natural,which is inconvenient for the patient to use;(3)the prosthetic wrist's function is single,the volume and mass are too large.How to solve these problems is a significant research topic.The main research work and research results of this paper are as follows:(1)This paper explores the shape characteristics of human hand and the basic laws of grasping movement,providing a theoretical basis for the structure design of humanoid dexterous hand.The results of human hand physiology showed that skeleton muscle structure of human hand determine its morphological characteristics and motion function.The morphological analysis of human hand shows that there is a statistical rule between the length and relative position of five fingers.The results of functional analysis of human hand movement show that the human hand is highly redundant in the process of daily grasping motion,and the structure of the wrist is similar to a parallel mechanism of a rotating pair and a universal joint.(2)Proposed the design index of the humanoid dexterous hand and designed the compact mechanism of the dexterous hand.Based on the shape characteristics of human hand,the shape design of the dexterous hand is carried out,the length and relative position of each finger are determined respectively.A method for designing the driving mechanism of dexterous hand was proposed based on the law of human hand grasping movement.Then,according to the law of wrist motion,the structure design scheme of the dexterous wrist is put forward,and a wrist mechanism of "active flexion and extension & passive rotation" is designed.(3)Using a dexterous hand control method with three threshold decision,the grasp-ing performance of the humanoid dexterous hand was tested experimentally.The experimental results show that the humanoid dexterous hand has good grasping ability and the wrist mechanism can adjust the hand position effectively.