On the landscape of solutions to deal with delicate objects, the development and use of soft grippers is a topic of increasing interest, with a large number of prototypes proposed by the research community employing non-linear soft materials and based on diverse actuation means. However, increasing compliance usually leads to the reduction of lifting capacity. As a recent promising approach, shear forces exerted by a soft gripper can be enhanced by exploiting the electro-adhesion (EA) effect. Following this research trend, this paper proposes a new gripper that combines a compliant finger structure, with geometry taken from the FESTO FinRay but made of a softer material (a urethane rubber), and custom EA pads that are placed on the fingers at the interface with the grasped object. Following hyper-elastic model identification of the considered material and preliminary functional verification of gripper design via finite element simulations, the gripper is then manufactured and tested by means of a specific setup, replicating the grasping and lifting of cylindrical objects with different diameters. The results clearly show that the new gripper makes it possible to generate holding forces similar to those of the FESTO FinRay, but with significantly lower pressures on the grasped object (77 % less). Besides enabling the handling of more fragile items, the drastic increase in gripper compliance also results in lower mechanical actuation force (namely, 71 % less of gripping energy) required to generate the same holding force, with a consequent reduction of operation costs and sustainability of its application.

中文翻译：

---

增强顺应性夹具性能：利用电粘附力来增加提升力而不是抓取力


在处理精致物体的解决方案领域，软夹具的开发和使用是一个越来越受关注的话题，研究界提出了大量采用非线性软材料并基于不同驱动方式的原型。然而，增加合规性通常会导致起重能力的降低。作为最近有前途的方法，可以通过利用电粘附（EA）效应来增强软夹具施加的剪切力。遵循这一研究趋势，本文提出了一种新型夹具，它结合了顺应性手指结构、几何形状取自 FESTO FinRay 但由较软的材料（聚氨酯橡胶）制成，以及放置在手指界面处的定制 EA 垫与所抓握的物体。在对所考虑的材料进行超弹性模型识别并通过有限元模拟对夹具设计进行初步功能验证后，然后通过特定的设置来制造和测试夹具，复制不同直径的圆柱形物体的抓取和提升。结果清楚地表明，新型夹具可以产生与 FESTO FinRay 类似的夹持力，但对抓取物体的压力显着降低（减少 77%）。除了能够处理更易碎的物品外，夹具柔顺性的大幅增加还可以降低产生相同夹持力所需的机械驱动力（即，夹持能量减少 71%），从而降低运营成本和可持续性它的应用。