Structural Design And System Simulation Of A New Multi Fingered Dexterous Hand

The size of traditional multi-finger dexterous hand is fixed,resulting in limited working space and being unable to adapt to different sizes and shapes of objects.Aiming at the contradiction between the size of the dexterous hand and the working space,this paper proposes a new underactuated multi-finger dexterous hand structure.Dexterous hand adopt a three finger and three joint structure.The three fingers include a fixed finger and two movable fingers.The movable finger can rotate freely on the palm of the hand.The three joints consist of a moving pair and two rotating pairs.The moving pair can play the role of extending the finger.This structure solves the contradiction that the size of the dexterous hand and the grabbing space cannot be taken into account,and can be grasped adaptively while maintaining dexterity.Using Solidworks to create a three-dimensional model of the dexterous hand,the configuration of a dexterous hand grasping different objects is simulated;a grabbing method based on fingertip friction is proposed for a small-size object.Next,the D-H parameter method is used to solve the forward and reverse kinematic formulas of the dexterous hand,and the speed of the dexterous hand is analyzed using the Jacobian matrix,which lays a theoretical foundation for trajectory planning.In this paper,the trajectory planning of dexterous hands is performed on the basis of the three-time non-uniform rational B-spline optimization principle based on the shortest path optimization,and compared with the cubic polynomial and cubic B-spline trajectory planning methods to verify the three non-uniform rational B-spline effectiveness and reliability.Finally,the dynamic equation of dexterous hand is established by using Lagrange method,the model of transmission rope is constructed based on ADAMS,and the dynamics simulation is carried out to analyze the joint torque of the dexterous hand under working condition.The theoretical torque curve based on MATLAB was plotted and compared with the simulation results of ADAMS.The error is within a reasonable range,which verifies the correctness of dynamical theory analysis.