This paper presents a design methodology of a hydraulically-driven soft robotic gripper for grasping a large and heavy object -- approximately 10 - 20 kg with 20 - 30 cm diameter. Most existing soft grippers are pneumatically actuated with several hundred kPa pressure, and cannot generate output force sufficient for such a large and heavy object. Instead of pneumatic actuation, hydraulic actuation has a potential to generate much larger power by several MPa pressure. In this study, we develop a hydraulically-driven soft gripper, in which its basic design parameters are determined based on a mathematical model that represents the relationship among the driving pressure, bending angle, object mass and grasping force. Moreover, we selected materials suitable for grasping a heavier object, based on the finite element analysis result of the detailed design. We report experimental results on a 20 kg object grasping and closed-loop control of the finger bending angle.

翻译：本文提出了一种液压驱动软体机器人抓取器的设计方法，用于抓取直径约20-30厘米、重量约10-20公斤的大型重物。现有的大多数软体抓取器采用气压驱动，工作压力为数百kPa，无法产生足以抓取此类大型重物的输出力。与气压驱动相比，液压驱动通过数MPa的压力具有产生更大功率的潜力。在本研究中，我们开发了一种液压驱动软体抓取器，其基本设计参数基于一个数学模型确定，该模型描述了驱动压力、弯曲角度、物体质量与抓取力之间的关系。此外，基于详细设计的有限元分析结果，我们选择了适用于抓取更重物体的材料。我们报告了抓取20公斤物体的实验结果以及手指弯曲角度的闭环控制。