Research On One Underactuated Three-finger Dexterous Hand Drived By Tendon

As a robot manipulator tool that come into direct contact with the environment,robotic hand is a significant part of all kinds of robots. Underactuated manipulator hasbecome a hotspot in research of robot in recent years because of its less driving elementto drive multiple degrees of freedom at the same time, good shape adaptability, andsimple control at the same time. And tasks under the environment of nuclear accidentdisaster relief puts forward higher requirements on manipulator, including grabbingreliable, convenient for nuclear protection, easy to realize remote operation, light inweight as far as possible, etc. Therefore, the study of the underactuated dexterous handis of great significance.In this paper, according to the specific operation tasks of a nuclear accident disasterrelief, considering the complex and tough conditions under nuclear accident at the sametime, it puts forward a kind of design scheme of one underactuated dexterous handwhich is of three fingers and drived by tendon. And the dexterous hand (a total of sixdegrees of freedom) is driven by single motor which can realize the crawl. At the sametime, the dexterous hand can adaptive various objects of different shapes, grab reliable,and has good shape closed nature. Using SOLIDWORK software to establishthree-dimensional model of the dexterous hand with underactuated, and the dexteroushand is detailed mechanical structure design.Kinematics analysis was carried out on the underactuated dexterous hand, andusing coordinate matrix, it establishs the changing relation of coordinate system of thedexterous hand between the end contact coordinate system and the palm of your hand.The position equation of the end of the dexterous hand finger is derived, and it furtherdraws the work space of the dexterous hand. The statics model of grabbing of theunderactuated dexterous hand is set up, and the expression of contact force betweenfingers and objects is achieved, and at the same time, it gets the parameters whichinfluence the finger grasping force. A dynamic analysis was carried out on theunderactuated finger at the same time, and it achieved the relationship between thefinger drive moment of each joint and the angle of each joint, lays a foundation for thecontrol of the dexterous hand.Typical tasks(open the door) for dexterous hand needs to be completed, this papercompares and analyzes the different formation when the dexterous hand grasp thehandle. In order to make force smaller, stress relatively uniform as the goal, it gets anoptimization range of the dexterous hand grasping the handle; Optimize the pulleyradius and spring stiffness of each joint which influence directly the stand or fall of performance of the dexterous hand.It established the joint simulation platform for underactuated dexterous hand basedon ADAMS and MATLAB/Simulink software. Then it makes joint motion simulationrespectively for underactuated dexterous hand when grasping rules shape object andirregular shape object. Observe the underactuated fetching process of a dexterous hand,verify the rationality of the design of dexterous hand, envelope grasping and holdingfeatures, as well as the adaptability of different shape objects.