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

本研究旨在构建一个具有拇指的机械手系统，该系统可以根据给定的任务在较宽的运动范围内实现手指或手掌的对抗。在设计阶段，我们确定手具有径向对称的结构，可以抓取各种形状的物体，而这种结构在某种意义上是劣势的，因为类似于人的机器人手在教学操作中具有优势。我们还认为重要的是，每个手指都有一个兼容的覆盖物来与物体进行实际接触，因为这样的转换可以提高对抗性能，期望在更宽的运动空间中，手可以进行基于对抗的抓取。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），它的每个元件都具有3轴力和滑动振动传感功能，用于定位覆盖物中的物体并监测面接触状态。在系统的硬件部分，我们制造了7个DTS元件，排列在聚氨酯基覆盖物的表面，每个元件都是隔离的。由于DTS的传感噪声较大，不能充分利用实际的传感器信息。然而，在软件中，我们进一步研究了利用有限元法制定定位算法，以及利用起源于弹性覆盖层的势函数掌握稳定性评估算法。最后，我们评估了它们的有效性，并实时验证了这些计算。

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.