A robot hand using electro-conjugate fluid: Grasping experiment with balloon actuators inducing a palm motion of robot hand

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a jet flow (ECF jet) when subjected to high DC voltage. It is known that a strong ECF jet is generated under nonuniform electric field, for example, the field with a pair of needle and ring electrodes. We developed in our previous study a novel five-fingered flexible robot hand using the ECF. In this study, in order to improve the ECF hand we pay our attention to the flexion of palm because human often grasp an object with the flexion of palm. First, we propose a concept of five fingered robot hand which has balloon actuators driven by the ECF jet to produce the flexion of palm. The actuator is mainly composed of silicone rubber membrane and a rubber base with a slit, so that when the actuator is pressurized, the slit is opened, resulting in making the palm of the robot hand actuate. Finally we conduct grasping experiments based on Cutkosky's taxonomy of human grasping, and demonstrate the robot hand can grasp some objects with various shapes without any complex controller. The height, the width and the mass of the robot hand are approximately 70 mm, 40 mm and 40 g, respectively.