Compost Magazine

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This Young Engineer Just Made Robot Parts Compostable…

25th April, 2023

With the advent of AI and development in robotics, a future is fast approaching when much of your work (and maybe your composting too!) could be done by robots.

But what will happen when those robots come to their end of life? Will it lead to a new endless stream of waste that will further damage our planet?

Maybe not!

A team of engineers, led by CU Boulder graduate student Ellen Rumley, have created new biodegradable robot parts. 

The first is a new kind of robotic actuator or “artificial muscle”. 

This muscle can power robotic arms and legs with life-like movements, and best of all it can decompose in composting facilities.

The muscle is made from gelatin and commercially sourced degradable oils and bioplastics. 

The team built the material to a European standard which ensured the muscle would undergo at least 90% decomposition over 6 months. 

When the researchers simulated composting conditions, they found that the muscle had started to decompose after one month. 

After 50 days, only traces of the muscle were left.

When the muscle comes to the end of its life, it can be composted in an industrial facility, turned into biomass, and returned to the soil. 

The nutrients from the compost can then be used to grow new plants. 

Some of these plants can be used as raw material – or chemically synthesized into other materials – for robotic applications. 

Graphical representation of the lifecycle of a robot's hand using new compostable materials.

This revolutionary design is particularly exciting for applications that require components designed for single or short-term use, such as food handling or medical applications. 

However, it can also be used for longer-lasting applications, as the researchers found the muscles could move more than 100,000 times without failure. 

The team’s final designs for artificial muscles can lift nearly as well as ordinary actuators and will degrade in a composting facility in about 6 months. 

The team didn’t stop at the muscle, either!

They also developed a robot gripper that was built from biodegradable materials and is compatible with existing robot arms. 

Ellen told us there is the potential to do more in the future, too, explaining that while it might be difficult to switch to biodegradable power suppliers, she saw no reason why other components couldn’t be biodegradable. 

As research develops, Ellen believes that the biodegradable elements also could prove superior to standard materials: 

We’ve seen interesting electrical properties of certain biodegradable films, that, with some slight material optimization, could potentially be leveraged to make artificial muscles that are stronger than traditional versions. 

This is not inherent to biodegradability, but rather a happy coincidence.

Ellen did warn that biodegradability is not an excuse for overuse:

…just because it’s decomposable, doesn’t mean we should go through an unnecessary quantity of these components, which could lead to more harm than good. 

Many other factors can then come into play, such as transportation fuel, methane production during composting, and energy usage during product manufacturing due to increase in demand.

So let’s welcome the robots of the future, use (but not overuse!) them –  and compost them when they come to the end of their life.

Read the full study

Rumley et al, 2023, Biodegradable electrohydraulic actuators for sustainable soft robots, Science Advances

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