Research On 1:1 Proportional Humanoid Four-fingered Dexterous Hand For Power Grasping

Experts and scholars have done a lot of research on dexterous hand's structure,driving,grasp planning method,grasp force distribution,grasp stability and grasp operation.But because when the dexterous hand grasp the object powerfully,contact's position and contact force is not easy to determine,the more degree of freedom and the more complex structure,the worse of the stiffness,the weaker of the grasping ability.Therefore,most of the research on dexterous hands is concerned with the dexterity of its operation,the research of power grasping is less.This topic is the design and research of the humanoid four-fingered dexterous hand for the power grasping,considering its ability to grasp,the driving motor will be integrated in the forearm,because the drive motor is not limited by the size of the fingers or palm,greatly increased the driving capability.Thinking the structure of the finger,using two motor to drive finger base joint which has two degrees of freedom,Can provide 2 times the grab force.The middle joint and the end joint with reference to the movement characteristics of the human hand,designed as wire coupling mechanism to achieve 1: 1 precision transmission,design joint torque sensor to detect joint torque,and according the joint angle sensor,we can get the finger contact force information.Then,the kinematics analysis and dynamic analysis of the dexterous hand are carried out,which lays the theoretical foundation for the follow-up dexterous grasping simulation.Given the finger of the joint movement characteristics in the ADAMS,a single finger dynamic simulation was performed to verify the correctness of the dynamic derivation.In the magic hand to grasp the 5kg cylinder for static analysis,with the optimization algorithm to obtain a stable grasp of the joint angle of the fingers,knuckle and the contact point of the contact and the contact force.And then according to the torque balance to get the joint drive torque,according to the calculated drive torque,select the appropriate drive motor.In the ADAMS to the dexterous hand to exert the driving torque,performing power grasping simulation,stable grasp of the object can prove the rationality of the selected motor.Based on the force / position hybrid control,we do ADAMS-SIMULINK simulation,gets joint angle and contact point position and contact force information.Finally,according to the contact information obtained by the ADAMS simulation,it is applied to the finite element model.When the dexterous hand grasp the 5kg object,the strength and stiffness requirements can be met.On the basis of this,the motive force is obtained under the premise of satisfying the motor driving ability.The maximum grabable 7.5kg of objects.The modal analysis and harmony analysis gets the natural frequency of the dexterous hands,we can choose according the best working frequency when the dexterous hand working.