Structural Design And Control Research Of A Modular Flexible Dexterous Hand

With the continuous development of science and technology,the robot end gripper represented by the dexterous hand plays an increasingly important role.Because it can complete the grasping operation under various complex tasks,it has become an essential part of the field of robotics in future research direction.Firstly,this paper proposes a modular two-degree-of-freedom full-drive finger mechanism,which includes two drive sources and two joints,each joint can move independently,and the transmission form is link transmission.The rationality of the design of the finger mechanism is verified by finite element analysis of the finger mechanism.A flexible member spring is designed between the drive motor and the connecting rod,and the finger can output flexibly by analyzing and verifying the grasping force at the end of the finger.A variable three-finger palm mechanism is proposed,the palm can drive the fingers to distribute in different configurations,forming three grasping modes:unilaterally arranged grasping,opposite-side arranged grasping,and uniformly arranged grasping,which is suitable for grasping needs of different tasks.Secondly,the forward and inverse kinematics modeling and analysis of a single finger mechanism are carried out in this paper.Because the dexterous hand is complex and highly integrated,it is necessary to simplify one finger into a linkage mechanism,and model the single-finger pose for each finger.Based on the four-bar linkage,geometric relationship and Euler equation,the forward and inverse mapping is performed from the actuator space to the joint space and then to the finger end position space,and the forward and inverse kinematics model of the finger is obtained.Drawing the finger’s workspace in Matlab and analyzing it to get the grasping advantage over the underactuated hand.Finally,the control test of the physical prototype of the fingers and palm of the dexterous hand is carried out,and the grasping simulation analysis of three different configurations of the dexterous hand is carried out.In this paper,a prototype of the three-finger dexterous hand is built and the control grip test is carried out.The related mode of connecting the PC terminal to the drive motor and sending commands,as well as the impedance control of the drive motor and the model and impedance control of the damping-spring-mass system are designed principle model.Grasping simulation of three grasping modes of dexterous hand:unilateral grasping,contralateral grasping and 120°uniform grasping,and analyzed the change of the contact force between the finger joint and the target object and grasping,the change of the position of the center of mass of the motor push rod when the object is used,and it is concluded that all three modes can be stably grasped.The analysis shows that the designed three-fingered dexterous hand can adapt to different tasks and has strong practicability.