关键词: 欠驱动, 永磁关节, 磁复位力矩, 变刚度, 仿生五指机械手

Abstract: In order to reduce the difficulty of control system and achieve flexible grasping of objects,a new type of underactuated flexible permanent magnet bionic five-fingered hand mainly driven by tendon rope traction was proposed. First,the structure and working principle of the permanent magnet joint were introduced. Second,the permanent magnet joints were designed in series to construct the bionic index fingers. The magnetic circuits of the permanent magnet joints were simulated and calculated,and the distribution of magnetic field lines and magnetic reset torque values of the permanent magnet joint were solved. Then,taking the permanent magnet bionic index finger as an example,the grasping motion space of the bionic index finger was analyzed. Finally,the overall design of the underactuated flexible permanent magnet bionic five-fingered hand was carried out and the postures of grasping objects of different shapes were analyzed. This study shows that the permanent magnet joint is a variable stiffness flexible joint. By using tendon rope traction to control the sequential bending and rotation of each permanent magnet joint of bionic finger,the grasping action of human fingers can be simulated. The bionic five-fingered hand has 15 permanent magnet joints and 1 joint module,so there are a total of 16 degrees of freedom. However,there are only 6 driving components for control,which has a high underactuation. It is possible to achieve the control of a large number of joint degrees with a relatively small number of drivers,this will greatly reduce the difficulty of control. This research provides a new idea for the application of permanent magnet drive technology in the field of bionic manipulators and has certain engineering application value.

Key words: underactuation, permanent magnet joint, magnetic reset torque, variable stiffness, bionic five-fingered hand