Collapsible Gripper Inspired by Earwig Wings

Innovation: Academia

ETH Zurich & Purdue University

2018

Image: Hedera Baltica / Flickr / Some rights reserved

Manage Mechanical Wear

A living system is subject to mechanical wear when two parts rub against each other or when the living system comes in contact with abrasive components in its environment, such as sand or coral. Some abrasive components are a constant force, such as finger joints moving, while others occur infrequently, such as a sand storm moving across a desert. Living systems protect from mechanical wear using strategies appropriate to the level and frequency of the source, such as having abrasion-resistant surfaces, replaceable parts, or lubricants. For example, human joints like shoulders and knees move against each other all day, every day. To protect from mechanical wear, a lubricant reduces friction between the cartilage and the joint.

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Modify Size/Shape/Mass/Volume

Many living systems alter their physical properties, such as size, shape, mass, or volume. These modifications occur in response to the living system’s needs and/or changing environmental conditions. For example, they may do this to move more efficiently, escape predators, recover from damage, or for many other reasons. These modifications require appropriate response rates and levels. Modifying any of these properties requires materials to enable such changes, cues to make the changes, and mechanisms to control them. An example is the porcupine fish, which protects itself from predators by taking sips of water or air to inflate its body and to erect spines embedded in its skin.

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Gripper from ETH Zurich and Purdue University has a soft elastic joint that enables it to methodically self-unfold.

Benefits

Efficient
Tunable
Reduced energy usage
Lightweight

Applications

Robotics
Prosthetics

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure

The Challenge

Traditional gripping robots use linkages, springs, and actuators in their appendages, which usually make them heavy and bulky, hindering their overall handling performance. Additionally, these mechanisms can require external energy or batteries, making the device less portable.

Innovation Details

The gripper is a synthetic folding system with self-folding and locking capabilities. It has stiff facets with rubber-like hinges. The mid-region is highly specialized so that it is stable in two states: folded and unfolded. The mechanism behind this stability involves the elastic energy stored in the folds on the mid-region. The gripper can fully deploy and hold on to objects without external energy.

Biomimicry Story

In a resting state, earwigs have hidden wings that are folded like origami and stowed. When escaping a predator or attacking prey, they quickly unfold their wings, expanding them to 10-times their initial size. Once the insects stop flying, they promptly fold and store their wings in the initial, resting position.

References

Journal article

Bioinspired spring origami

Science

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