Current surgical grippers rely on friction grip, where normal loads (i.e. pinch forces) are translated into friction forces. Operating errors with surgical grippers are often force-related, including tissue slipping out of the gripper because of too low pinch forces and tissue damaging due to too high pinch forces. Here, we prototyped a modular surgical gripper with elastomeric soft pads reinforced in the shear direction with a carbon-fiber fabric. The elastomeric component provides low normal stiffness to maximize contact formation without the need of applying high normal loads (i.e. pinch forces), whereas the carbon-fiber fabric offers high shear stiffness to preserve the formed contact under the lateral loads (i.e. shear forces) that occur during tissue lifting. Additionally, we patterned the pads with a sub-surface micropattern, to further reduce the normal stiffness and increase shear stiffness. The body of the prototype gripper, including shaft, joints, and gripper tips, was fabricated in a single step using 3D printing, followed by manual attachment of the soft pads to the gripper. The gripping performance of the newly developed soft gripper on soft tissues was experimentally compared to reference grippers equipped with metal patterned pads. The soft-pad gripper generated similar gripping forces but significantly lower pinch forces than metal-pad grippers. We conclude that grippers with anisotropic-stiffness pads are promising for secure and gentle tissue grip.

当前的手术抓手依靠摩擦抓握，其中法向载荷（即夹紧力）被转化为摩擦力。手术夹持器的操作错误通常与力有关，包括由于过小的挤压力而导致组织从夹持器中滑出，以及由于过大的挤压力而损坏组织。在这里，我们制作了一个模块化手术抓手的原型，该抓手带有在剪切方向上用碳纤维织物加固的弹性软垫。弹性部件提供低法向刚度以最大限度地形成接触，而无需施加高法向载荷（即挤压力），而碳纤维织物提供高剪切刚度以在横向载荷（即剪切力）下保持形成的接触发生在组织提升过程中。此外，我们用亚表面微图案对焊盘进行了图案化，进一步降低法向刚度并增加剪切刚度。原型夹持器的主体，包括轴、接头和夹持器尖端，使用 3D 打印在一个步骤中制造，然后将软垫手动连接到夹持器上。新开发的软夹具在软组织上的夹持性能与配备金属图案垫的参考夹具进行了实验比较。软垫夹持器产生类似的夹持力，但比金属垫夹持器产生的夹持力要低得多。我们得出结论，带有各向异性刚度垫的夹持器有望实现安全和轻柔的组织抓握。然后将软垫手动连接到夹具上。新开发的软夹具在软组织上的夹持性能与配备金属图案垫的参考夹具进行了实验比较。软垫夹持器产生类似的夹持力，但比金属垫夹持器产生的夹持力要低得多。我们得出结论，带有各向异性刚度垫的夹持器有望实现安全和轻柔的组织抓握。然后将软垫手动连接到夹具上。新开发的软夹具在软组织上的夹持性能与配备金属图案垫的参考夹具进行了实验比较。软垫夹持器产生类似的夹持力，但比金属垫夹持器显着降低夹持力。我们得出结论，带有各向异性刚度垫的夹持器有望实现安全和轻柔的组织抓握。