Low-Energy Burrowing Robot Inspired by Razor Clams

Innovation: Academia

MIT

2016

Image: Jonathan Farber / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Move in/on Solids

To obtain needed resources or escape predators, some living systems must move on solid substances, some must move within them, and others must do both. Solids vary in their form; they can be soft or porous like leaves, sand, skin, and snow, or hard like rock, ice, or tree bark. Movement can involve a whole living system, such as an ostrich running across the ground or an earthworm burrowing through the soil. It can also involve just part of a living system, such as a mosquito poking its mouthparts into skin. Solids vary in smoothness, stickiness, moisture content, density, etc, each of which presents different challenges. As a result, living systems have adaptations to meet one, and sometimes multiple, challenges. For example, some insects must be able to hold onto both rough and slippery leaf surfaces due to the diversity in their environment.

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Move in/on Liquids

Water is not only the most abundant liquid on earth, but it’s vital to life–so it’s no surprise that the majority of life has evolved to thrive on and under its surface. Moving efficiently in and on this dense and dynamic substance presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag, utilize surface tension, fine tune buoyancy, and take advantage of various types of currents and fluid dynamics. For example, sharks can slide through water by reducing drag due to their streamlined shape and specially shaped features on their skin.

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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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Burrowing robot from MIT uses contracting valves to induce a quicksand effect in the surrounding soil, enabling the robot to dig down.

Benefits

Reduced energy usage
Autonomous

Applications

Underground exploration
Security and defense systems
Marine construction

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure

The Challenge

Robots require energy to operate, often in the form of a battery. Autonomous robots must carry the battery with them. Unfortunately, batteries tend to be large and heavy, which interferes with the performance of the robot. Additionally, moving through solids such as soil consumes more energy than moving in air.

Innovation Details

The burrowing robot, also called “RoboClam,” is constructed of two halves connected by a rod. The rod moves the halves up and down, together and apart. The contractions and expansions quickly release liquid around the robot causing a quicksand effect called liquefaction in the surrounding sand. When the sand liquefies, the robot can propel downward.

Biomimicry Story

Razor clams are known for their ability to burrow into the ocean floor, even with their rigid shell structures. To do this, the clam expands and contracts its valves, releasing liquid and fluidizing the surrounding sand, which allows the razor clam burrow down.

See Related Strategy

Biological Strategy

The Atlantic Razor Clam’s Double-Anchored Wriggle Dive

Atlantic razor clam

The valves of the Atlantic razor clam reduce drag and the amount of energy required to reach burrow depth by contracting to locally fluidize the surrounding soil.

References

Journal article

An Experimental Investigation of Digging Via Localized Fluidization, Tested With RoboClam: A Robot Inspired by Atlantic Razor Clams

Journal of Mechanical Design

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