The Design And Study On Mechanism And Sensor System Of Prosthetic Hand

The purpose of this research is to invent a multi-degree prosthetic hand with low-weight, small-volume, high-reliability, easy control algorithm and satisfied manipulative performance. The innovative underactuation theory and coupling theory are introduced in this paper. The contradiction between multi-DOF and dexterity of prosthetic hand are resolved. On the premise of low-weight and small-volume, the hand is also dexterous enough. Simultaneously, the shape and the locomotion way are almost the same as people's.First of all, the paper carries out an extensive research on the state-of-the-art development of dexterous hand and prosthetic hand, and analyzes the trend of prosthetic hand development. Based on the study above, a design scheme based on underactuation coupling theory is put forward.Secondly, based on previous prosthetic hands developed in DLR-HIT lab, improvements have been made. Four-linkage structure is used to accomplish underactuation and coupling of the finger, the demension of this finger are modified and mini-bearings are introduced in the joint in order to improve the dexterity and reliability. In order to improve the coherence of the movement of three fingers and maitain the grasp stance, the torque spring based structure is improved. Simulation of grasping objects with various figures are completed to determine the position of thumb; Torque sensor which can be interconverted is designed to measure base joint torque. Structure of prosthetic hand is designed based on modularization and integration thinking, and the structure, sensor, controlling and driving circuit system are integrated in the prosthetic hand.Static modeling of the underactuating finger of prosthetic hand is founded and the relationship of driving torque and received-force of each phalanx is obtained when grasping various objects. Parameters of the coupling linkages are designed and the structure parameters of the coupling linkages are made certain. The pro/E model of prosthetic hand is built and Adams simulation is accomplished. The dynamics of first finger proved by the Matlab simulation and Adams simulation is constructed.Finally based on the signal of torque sensor and TMC428 force control is completed. Then adaptability and dependability experiment of prosthetic hand are implemented.