Construction of A Robot Hand System with A Thumb Based on the Concept of Opposition

本研究旨在构建一种具有拇指的机器人手系统，根据给定的任务，在较大的运动范围内实现手指或手掌的对位。在设计阶段，我们确定了手具有径向对称的配置，用于抓取各种形状的物体，而该配置的劣势在于，由于相似，仿人机器人手在教学操作中具有优势。我们还认为，每个手指都有一个顺从的覆盖物来与物体进行区域接触是很重要的，因为这样的转换改善了对手的表现，期望有一个宽广的运动空间，在这个空间中，手可以进行基于对手的抓取。我们还设计了一种先进的触觉传感器，称为动态触觉传感器(DTS)，每个元件都具有三维力和滑动振动传感功能，用于定位覆盖物中的对象并监测区域接触状态。在系统的硬件上，我们制作了7个元件布置在尿素基覆盖物的表面，每个元件相互隔离。由于DTS存在显著的传感噪声，无法充分利用实际的传感器信息。在软件中，我们进一步研究了利用有限元建立定位算法，以及利用源于弹性覆盖的势函数进行稳定性评估的算法。最后，我们对其有效性进行了评估，并对计算结果进行了实时验证。

This study aims at constructing a robot hand system with a thumb which realizes in a wide motion range finger-or palm-opposition depending on the task given. At the design stage, we determine the hand to have a radially symmetrical configuration for grasping objects in various shapes, while the configuration is inferior in the sense that a human-like robot hand is advantageous in teaching operation because of the similarity. We also considered it important that each finger has a compliant covering to make an areal contact with an object since such a convering improves the opposition performance expecting a wide motion space in which the hand behaves opposition-based grasping. We also designed an advanced tactile sensor, called dynamic tactile sensor (DTS) each element of which has both 3-axis force and slip vibration sensing functions, for localizing an object in the covering and monitoring the areal contact state.In the hardware of the system, we manufactured 7 elements of DTS arranged on the surface of a urethan-based covering, with each element being isolated. Because of the remarkable sensing noise from the DTS,we could not utilize the practical sensor information. However in the software, we studied further on formulating localization algorithms using FEM as well as grasp stability assesment algorithms using a potential function originated in the elastic covering. Finally, we evaluated thier effectiveness and verified those computation in a real-time manner.