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Soft robotics, including soft grippers and manipulators, are increasingly required to function more adaptively and securely in unknown environments. However, conventional soft pneumatic grippers often grasp and hold objects via the active bending of multiple fingers, making it challenging to grip and hold, for example, spiny objects safely because of the potential damage to the pneumatic chambers. In this letter, inspired by the entanglement behavior of plant tendrils, we propose a soft, pneumatic, fail-safe gripper. The fail-safe property is guaranteed by two mechanisms, the passive entanglement and the redundant contacts. Specifically, the gripper exploits an array of tentacle fingers that actively extend and passively entangle for entanglement grasping. To understand the working principle, we studied the entanglement behavior of a single tentacle finger by both analytical modeling and finite element method simulation. We also characterized the griping capability of this gripper in a series of different grasping experiments. The gripper was demonstrated to be capable of grasping a range of different objects, from artificial ones with simple shapes to real-world targets with complex shapes. We finally showcased the fail-safe property of this gripper in a pick-and-lift task by comparing the performance of this gripper with that of a conventional gripper when the two grippers are manually damaged. This work paves the way for the development of soft pneumatic grippers with fail-safe and reliable grasping.

Gripping slippery and flexible tissues during minimal invasive surgery (MIS) is often challenging using a conventional tissue gripper. A force grip has to compensate for the low friction coefficient between the gripper’s jaws and the tissue surface. This study focuses on the development of a suction gripper. This device applies a pressure difference to grip the target tissue without the need to enclose it. Inspiration is taken from biological suction discs, as these are able to attach to a wide variety of substrates, varying from soft and slimy surfaces to rigid and rough rocks. Our bio-inspired suction gripper is divided into two main parts: (1) the suction chamber inside the handle where vacuum pressure is generated, and (2) the suction tip that attaches to the target tissue. The suction gripper fits through a ∅ 10 mm trocar and unfolds in a larger suction surface when being extracted. The suction tip is structured in a layered manner. The tip integrates five functions in separate layers to allow for safe and effective tissue handling: (1) foldability, (2) air-tightness, (3) slideability, (4) friction magnification and (5) seal generation. The contact surface of the tip creates an air-tight seal with the tissue and enhances frictional support. The suction tip’s shape grip allows for the gripping of small tissue pieces and enhances its resistance against shear forces. The experiments illustrated that our suction gripper outperforms man-made suction discs, as well as currently described suction grippers in literature in terms of attachment force ( 5.95 ± 0.52 N on muscle tissue) and substrate versatility. Our bio-inspired suction gripper offers the opportunity for a safer alternative to the conventional tissue gripper in MIS., Medical Instruments & Bio-Inspired Technology