Functioning of Intelligence and Dexterity in Multi-Fingered Hands by Sensory-Motor Coordination

首先，通过考虑滚动接触约束，以显式的方式建立了基于手指-拇指对位的夹持模型。在本研究项目下，在假设指端为半球形但刚性的情况下，对夹持运动的动力学稳定性进行了分析。该项目最值得注意的成果总结如下：1)即使是一双机器手指闭上眼睛也能像人一样抓取物体，也能实现盲抓取；2)通过引入灵巧度指数，以拇指和食指不同关节之间的角色分担为目标，实现两个或多个手指在三维空间中的运动，实现三维稳定抓取。在不考虑三维空间中滚动接触的非完整约束的情况下，可以严格推导出具有非完整约束的完整手指-物体系统模型。然后从理论上证明了在物体具有两个平行平面的情况下，存在手指-拇指反作用力信号，从而实现了动态意义上的稳定捏合。完成了三自由度三维手指的设计，所有必要的机械部件都已制作或收集完毕。只剩下利用这对3-D机器人手指进行3-D稳定抓取实验。

Pinching based on the finger-thumb opposition was first modeled in an explicity way by taking into account rolling contact constraints. Under this research project, stability of pinching motions in a dynamic sense is analyzed under the assumption that finger-ends are of hemispherical shape but rigid. The most noteworthy outcomes under this project must be summarized in the followings : 1) "Blind grasping" can function even in the case of a pair of robot fingers likely as human grasp on object even if they close eyes and 2) "Dexterity Analysis" can be done through introducing "dexterity index" and aiming at role-sharing among different joints of thumb and index finger.The final goal of the project is to realize 3-Dimensional stable grasping by means of two or more fingers with multiple joints moving in 3-Dimensional space. Regardless of the non-holonomic constraint of rolling contacts in 3-D space, a whole fingers-object system model with non-holonomic constraints could be derived in a rigorous way. Then, it is shown theoretically that there exists a signal of fingers-thumb opposition force that realizes the stable pinching in a dynamic sense, provided that the object has two parallel flat surfaces.Design of a 3-Dimensional finger with 3 DOFs has been finished and all necessary mechanical parts are made or collected now. Only it remains to carry out the experiment of 3-D stable grasping by using this pair of 3-D robot fingers.