Soft grippers have excellent adaptability for a variety of objects and tasks. Jamming-based variable stiffness materials can further increase soft grippers' gripping force and capacity. Previous universal grippers enabled by granular jamming have shown great capability of handling objects with various shapes and weight. However, they require a large pushing force on the object during gripping, which is not suitable for very soft or free-hanging objects. In this paper, we create a novel palm-shape anthropomorphic variable-stiffness gripper enabled by jamming of 3D printed fabrics. This gripper is conformable and gentle to objects with different shapes, requires little pushing force, and increases gripping strength only when necessary. We present the design, fabrication and performance of this gripper and tested its conformability and gripping capacity. Our design utilizes soft pneumatic actuators to drive two wide palms to enclose objects, thanks to the excellent conformability of the structured fabrics. While the pinch force is low, the palm can significantly increase stiffness to lift heavy objects with a maximum gripping force of $17\,$N and grip-to-pinch force ratio of $42$. We also explore different variable-stiffness materials in the gripper, including sheets for layer jamming, to compare their performances. We conduct gripping tests on standard objects and daily items to show the great capacity of our gripper design.

翻译：软体夹爪对不同物体和任务具有优异的适应性。基于堵塞效应的变刚度材料能够进一步提升软体夹爪的抓取力和承载能力。此前基于颗粒堵塞的通用夹爪已展现出处理不同形状和重量物体的强大能力，但这类夹爪在抓取时需要对物体施加较大的推力，不适用于抓取极柔软或自由悬挂的物体。本文提出一种基于3D打印织物堵塞效应的新型掌形拟人化变刚度夹爪。该夹爪可贴合不同形状物体且作用轻柔，仅需极小的推力，仅在必要时增强抓取强度。我们阐述了该夹爪的设计、制造和性能，并测试了其贴合性和抓取能力。得益于结构化织物的优异贴合性，本设计采用软体气动驱动器驱动两个宽大的掌面包裹物体。在夹持力较低的情况下，掌面能显著增加刚度以举起重物，最大抓取力达17牛，抓取-夹持力比为42。我们还探索了夹爪中不同变刚度材料（包括用于层堵塞的薄片）的性能对比。通过对标准物体和日用品的抓取测试，验证了本夹爪设计的卓越性能。