A Bioinspired Soft Swallowing Robot Based on Compliant Guiding Structure.

From small unicellular organisms to large mammals, swallowing is an important way for them to interact with their external environment. The majority of these animals swallow their targets for the purpose of hunting, and some fish and amphibians protect their cubs from external injury by swallowing them. Thus, swallowing can produce an efficient capture, keep the integrity of targets, and provide effective protection for swallowed objects. Inspired by this, we propose a novel soft swallowing robot (SSR) capable of swallowing various objects that have different shapes and stiffnesses, protecting objects from squeeze and collision, and withstanding high temperature, which are enabled by a compliant guiding structure consisting of a double thin-walled capsule filled with fluid and a linearly movable traction body. In this article, we study the SSR supported by air and water, respectively; furthermore, we experimentally conclude that the working medium has a great influence on the inherent characteristics of the SSR. Our study helps lay the foundation for the research of soft robotic systems with swallowing characteristics, and the SSR is expected to enter the practical application field from the laboratory.

Design and modeling of a high-load soft robotic gripper inspired by biological winding.

The improvement of the load capacity of soft robotic grippers has always been a challenge. The load improvement methods of existing soft robotic grippers mainly include the development of soft actuators with high output force and the creation of closed gripping structures. Inspired by winding behaviors of animals and plants, we propose a high-load soft robotic gripper driven by pneumatic artificial muscles (PAMs) that combines the advantages of a high force soft actuator and a closed gripping structure. Most existing model formulations focus on characterizing the end force generated to the length contraction and applied pressure of PAMs. However, the focus of this work is to build the force model of PAMs in winding shape to analyze the tightening force of the high-load soft gripper, and the model is validated by a tightening force test. An experimental work is carried out to characterize the load capacity and multi-object gripping capacity of the high-load soft gripper. We experimentally prove that it can lift heavy objects that weigh up to 35.5 kg, which is more than 47 times its weight. This work contributes to the load improvement of soft robotic grippers, and the mathematical modeling of engineering systems with winding structures. The developed high-load soft gripper is expected to enter the practical application field from the laboratory.

High-Load Soft Grippers Based on Bionic Winding Effect.

The improvement of the load capacity of soft grippers has always been a challenge. To tackle this load capacity challenge, this work presents four novel types of high-load (HL) soft grippers that are bioinspired by bionic winding models. The winding models are found commonly in many animals and plants, where different winding patterns are used to grip different objects. Inspired by the winding models, we design four bionic winding structures that are driven by pneumatic artificial muscles (PAMs), and then four HL soft grippers are formed out of the winding structures. The inner cavities of the HL soft grippers contract after the PAMs are inflated, which enables objects to be wrapped to achieve gripping. Compared with most existing soft grippers, the HL soft grippers have a higher load capacity, and they can also grip various objects that have different shapes and stiffnesses without damaging them. In addition, in man-machine collaboration, operators can be in direct contact with them without being hurt. Our study helps lay the foundation for engineered systems with bionic winding structures.