Development Of Three-fingered Dexterous Hand Driven By Gear-tendon Mechanism

With the rapid development of robot technology,its application area is becoming more and more widely.The end effectors are key components of robot in interaction with the environment.The improvement of robot intelligent level and working ability is largely depended on the flexibility and reliability of its end executor.Therefore,in order to improve its flexibility,it is very significant to study the robot end executor.Generally,the robot end executor is divided into two kinds,one is the end gripper commonly used in the industrial robot,which has simple structure and can only achieve a single action.Another is the multi-fingered dexterous hand with more freedom and joints.Imitating the function of a human hand,it can grab a variety of objects with complex shape flexibly and operate finely.It can be applied to assistive devices and tasks in dangerous environment for liberating human's hands.It greatly expanded the application field of robot end executors,so it has wide development prospects.This paper developed a three-fingered dexterous hand driven by gear-tendon,based on a construction project of "Intelligent Service Robot Technology and Equipment Engineering Laboratory of Dalian".The major contents are as follows:Based on the basic function and anatomical structure of human hands,a three-fingered dexterous hand driven by gear-tendon is designed.A new type of spring-slider mechanism realized the under actuated finger in a good way.The passing way of double tendon rope effectively implemented the fingers' open and close.The three figures are just the same in modular design.Right triangle structure is used in the installation position can be realized to knead and envelope grab target movement.Then,the control system of the dexterous hand was designed,and an experimental platform was built,which provides the basis for the following research.In this paper,a workspace analysis method of single finger based on inverse kinematics was proposed.The method is only to solve the inverse kinematics of two degrees of freedom joints,and on this basis to analyze the working space of the third joint.Compared to the traditional method based on the forward kinematics,this method has small amount of mathematical calculation and good application value.Based on V-REP robot simulation software,the working space simulation of the humanoid three fingers dexterous hand in the positive kinematics solution has been carried on.And the simulation results has been analyzed,pointing out the shortage of the existing principle prototype.Based on the experimental prototype of three fingers humanoid dexterous hand,an experiment of fingers compliant ability under the non-work condition had been carried on,and verified the self-protection ability of the dexterous hand.Experiments of single finger control has been conducted,including the speed and position control,to determine the appropriate grab speed and control mode.Snatching different shapes of objects,including pinch and envelope grab,to verify the grasping performance of the dexterous hand,and the result of the experiment has been analyzed.Aiming at the existing problem of dexterous hand mechanism,parameters optimization of pulley drive system has been designed.The results show that the prototype transmission mechanism was simplified and the transfer efficiency was improved.Based on the experimental prototype of three fingers humanoid dexterous hand,after the analysis and determination of the dexterous hand control system architecture,the integrated design of the control system was projected.Firstly,the hardware of the integrated control system was designed,including the main control module STM32F103C8T6,driver module of electric motor DRV10970 and so on.The size of the PCB panel was only 50mm×70mm,which was similar with an adult palm.And then,the software of the integrated control system was programmed.According to each motor in the finger knuckles,to set the motor movement and combination movements of multiple fingers.Therefore,the feasibility of the prototype structure was verified.