3D-Printed Soft Robot Inspired by Insects

Innovation: Academia

University of California San Diego

2020

Image: Gouthaman Raveendran / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Manage Impact

An impact is a high force or mechanical shock that happens over a short period of time, such as a hammer hitting a nail rather than a hand pushing slowly against a wall. Because of their speed and force, impacts don’t allow materials to slowly adjust to the force, which can lead to cracks, ruptures, and complete breakage. Therefore, living systems have strategies that can absorb, dissipate, or otherwise survive that force without the need to add large amounts of material. For example, the Toco toucan’s large beak is very lightweight, yet can withstand impacts because it’s made of a composite material with rigid foam inside and layers of a hard, fibrous material outside.

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Physically Assemble Structure

Living systems use physical materials to create structures to serve as protection, insulation, and other purposes. These structures can be internal (within or attached to the system itself), such as cell membranes, shells, and fur. They can also be external (detached), such as nests, burrows, cocoons, or webs. Because physical materials are limited and the energy required to gather and create new structures is costly, living systems must use both conservatively. Therefore, they optimize the structures’ size, weight, and density. For example, weaver birds use two types of vegetation to create their nests: strong, a few stiff fibers and numerous thin fibers. Combined, they make a strong, yet flexible, nest. An example of an internal structure is a bird’s bone. The bone is comprised of a mineral matrix assembled to create strong cross-supports and a tubular outer surface filled with air to minimize weight.

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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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Soft robot from the University of California San Diego has a 3D-printed 'flexoskeleton' with both soft and rigid parts.

Benefits

Flexible
Interchangeable parts
Reduced costs

Applications

Robotics
Protective equipment

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure

The Challenge

Soft robots are typically made by adding soft materials to a rigid inner body. The process consists of multiple steps, including casting and machining. This increases the time, cost, and likelihood of mistakes.

Innovation Details

The soft robot is made of a ‘flexoskeleton’ that consists of a soft body and rigid outer components. It was inspired by the exoskeletons of insects, which have both soft and rigid flexible parts. The soft body is 3D printed with a rigid material on a thin sheet of polycarbonate that acts as a flexible base. The 3D printer controls the rigidity of the material it prints, allowing for a variety of different options. This method makes it easy to create a whole library of Lego-like components that can easily be swapped for one another as needed. One flexoskeleton component takes 10 minutes to print and costs less than one dollar; a whole robot can be printed in under two hours.

Biological Model

Insects have exoskeletons that protect their soft inner body from impact and damage. It is made from chitin fibers and is strong enough to resist impact but flexible enough to allow the insect to move freely.

See Related Strategy

Biological Strategy

Exoskeleton Adjusts to Structural Forces

Insects

Exoskeleton of insects adjusts to strain and load by changing thickness, stiffness, and fiber orientation.

References

Journal article

Flexoskeleton Printing Enables Versatile Fabrication of Hybrid Soft and Rigid Robots

Mary Ann Liebert Publishers

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