Bionic inspiration from human thumb and index finger was the drive to design a high-performance two-finger dexterous hand. The size of each phalanx and the motion range of each joint in the human thumb and index finger were summarized, and the features of three grasping patterns were described in detail. Subsequently, a two-finger dexterous bionic hand with 6 Degrees of Freedom (DoFs) was developed. Both the mechanical thumb and index finger were made up of three rigid phalanx links and three mechanical rotation joints. Some grasp-release tests validated that the bionic hand can perform three grasping patterns: power grasp, precision pinch and lateral pinch. The grasping success rates were high under the following cases: (1) when power grasping was used to grasp a ring with external diameter 20 mm – 140 mm, a cylinder with mass < 500 g, or objects with cylinder, sphere or ellipsoid shape; (2) when the precision pinch was used to grasp thin or small objects; (3) when the lateral pinch was used to grasp low length-to-width ratio of objects. The work provided a method for developing two-finger bionic hand with three grasping patterns, and further revealed the linkage between the difference in finger structure and size and the hand manipulation dexterity.

中文翻译：

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三种抓握模式的两指灵巧仿生手的研制-NWAFU手

人类拇指和食指的仿生灵感是设计高性能两指灵巧手的动力。总结了人的拇指和食指的每个指骨的大小和每个关节的运动范围，并详细描述了三种抓握方式的特征。随后，开发了具有6个自由度（DoF）的两指灵巧仿生手。机械拇指和食指均由三个刚性指骨连杆和三个机械旋转关节组成。一些抓握释放测试验证了仿生手可以执行三种抓握方式：力量抓握，精确捏和横向捏。在以下情况下，抓取成功率很高：（1）当使用动力抓取来抓取外径为20 mm – 140 mm的圆柱，质量小于500 g的圆柱时，或具有圆柱，球形或椭圆形形状的物体；（2）当使用精密捏抓细物体时；（3）当使用侧向捏紧来抓住物体的长宽比低时。该工作提供了一种开发具有三种抓握模式的两指仿生手的方法，并进一步揭示了手指结构和大小的差异与手操作灵巧性之间的联系。