Analysis And Configuration Of Underactuated Finger Based On Topological Graph With Grade Edge

Underactuated finger represent the kind of finger that the number of unactuated joint less than that of joint degrees of freedom. Based on the research contents of mechanism, structure and kinematics are analyzed of underactuated finger in this paper.Firstly, based on plane topological graph, common kinematic pairs are classified by their DOF, concept of spatial topological graph with grade edge is put forward. Spatial topological graph makes up the limitation of normal topological graph, which provide a general method for the description and configuration synthesis of Mechanism.Secondly, single-opened-chain and structure factor are analyzed, so generalized single-opened-chain is proposed which suitable for the configuration synthesis of underactuated finger. A typical underactuated finger with2DOF is taken as rudiment, based on topological graph with grade edge and generalized single-opened-chain, several kinds of dexterous fingers are synthesized by changing the elements in the topological diagram. At the same time, some feasible structure schemes are presented in this paper.Thirdly, Based on metamorphic mechanisms theory, a new analysis method of multi-DOF finger is put forward—configuration analysis. A3-phalanx underactuated finger with3-DOF is taken as example and four configurations during grasping-motion are defined, then underactuated mechanism is clearly explained by the changes of topological structure and DOF of underactuated fingers.Finally, human grasp property is analyzed, according to grasping adaptability and anthropomorphic, a3-phalanx finger with2-DOF is chosen from configuration library of underactuated dexterous finger in Chapter3. Kinematics equations are established by configuration classification and curves of velocity and acceleration of knuckle and fingertip are calculated. Trajectory of the fingertip at the two configurations is fitted by its coordinate position that measured in the kinematic experiment, which verified kinematics equations and configuration analysis by compared with theoretical calculation.