Robot Design Cheered for Being Like a Seed

It’s clever, and may help farmers, but common
Erodium plants do it naturally all the time.

Among the wonders of seed dispersal mechanisms in plants, the little ground weed called Erodium, commonly called stork’s-bill, has long attracted attention. It flings its seeds like spears away from the plant, then the spears coil up, roll on the ground and drill the seed into the soil. Changes in humidity and temperature coil up the “awn” (as the spear is called) into a finely-crafted drilling machine and automatic planter.

The story of the storks-bill seed was featured in Illustra Media’s short film Absolutely Awn-Some in its “Awesome Wonders” series and mentioned here in our 24 June 2020 entry. You can watch the film at that link or at the source: the John 10:10 Project website.

Humans Try to Catch Up

Now, robot designers at Carnegie Mellon University are boasting about their invention that uses a similar technique. It’s rather amusing to read the press reports about the “Engineered Magic” they performed. It sounds a bit like, “We applied our finest minds and used the latest materials in our high-tech lab to achieve a breakthrough that copies what a little weed does!” What do they expect, a standing ovation? Just go outside and watch nature do it.

Engineered Magic: Wooden Seed Carriers Mimic the Behavior of Self-Burying Seeds (Carnegie Mellon, 15 Feb 2023). Team lead Lining Yao smiles alongside photos of the device that look remarkably similar to the stork’s-bill seed all wound up and ready to drill. The device may look simple, but the embedded video shows that the engineers worked hard on the project. They had to be very careful selecting the right material, treating it for its function, and testing it in the field.

Inspired by Erodium’s magic, Lining Yao, the Cooper-Siegel Assistant Professor of Human-Computer Interaction at Carnegie Mellon University, worked with a team of collaborators to engineer a biodegradable seed carrier referred to as E-seed. Their seed carrier, fashioned from wood veneer, could enable aerial seeding of difficult-to-access areas, and could be used for a variety of seeds or fertilizers and adapted to many different environments. It’s an idea that Yao, the daughter of part-time farmers, has pondered since she was a Ph.D. student at MIT in the mid-2010s.

To be sure, their invention could extend seed dispersal far beyond the habitat of the stork’s-bill. It can also be upscaled to sow different kinds of crop seeds. That’s something Erodium can’t do. Yao’s team also gave their invention three awns or tails compared to Erodium’s one. This could help the seed plant itself upright, although stork’s-bill doesn’t seem to be handicapped in its self-burying score. Yao’s team also imitated the hair-like spikes on the seed itself that give the seed a grip when being shoved into the soil.

One thing Yao’s team did not copy, though, was the self-launching ability of Erodium seeds (see the Illustra film). Carnegie Mellon’s product has to be carried by a helicopter or drone. The seeds are dropped from compartments that must be opened to send them to the ground. Once on the ground, the manufactured awns respond to humidity like the Erodium seeds and begin the slow process of drilling themselves into the soil.

Yao’s paper with technical detail was published 15 Feb 2023 in Nature with the title, “Autonomous self-burying seed carriers for aerial seeding.”

Other Coverage

Self-burying robot morphs wood to sow seeds (Nature News and Views, 15 Feb 2023). This write-up by Mason & Nakayama calls the invention “elegant.”

A natural seed has inspired the design of a robot that can bury itself in soil when exposed to rainfall. The mechanism relies on the shape-changing properties of wood — a simple and elegant example of sustainable innovation.

This device corkscrews itself into the ground like a seed (Nature Video, 15 Feb 2023). A shorter video about the project compares the natural Erodium seeds with the robotic mimic. It explains how the inventions might be used, “if they can figure out large scale production of their devices.”

Artificial seed casing made from wood buries itself when wet (New Scientist, 15 Feb 2023). James Dinneen at New Scientist gave the invention good press:

Yao and her colleagues took inspiration from Elodium [sic, passim] and other plants with self-burying seeds to design a seed carrier that would be able to carry different sizes of seeds and twist into soil in different environments more effectively.

Dinneen reports that of “136 carriers, about 66 per cent of carriers successfully anchored in soil, and 39 per cent of seeds germinated.” The germination rate might have been higher, he notes, had not heavy rains dislodged half the seeds. The experiment gives proof of concept but further tests will be needed to see how useful the little wooden robots do in actual reseeding applications.

If they can get their E-seed carriers to make more E-seed carriers by reading internal codes and using available materials, then they will really have something to brag about. (The seed parts already will take care of their own reproduction.) Then, to really compete with the natural plants, they need to work on getting the self-generating E-seeds to launch themselves.

Nature couldn’t resist dragging Darwin into their video caption:

Plants have evolved all sorts of tricks to help their seeds spread and thrive. For some plants this means seeds that bury themselves in the soil to avoid getting eaten or dried out in the sun. Now a team of researchers are taking nature’s designs and engineering a new solution for planting crops, fertilising soil or replanting forests.

How silly is that? Nature’s designs evolved? It takes engineering to imitate what the Stuff Happens Law achieved? Come on. Design is design, not happenstance. Sadly, engineer Lining Yao repeated what had been drilled into her head through DODO education: “That’s a behaviour that’s been optimised through generations of evolution,” she remarked.

Watch the 5-1/2 minute Illustra film here. It was my pleasure to help collect some of the seeds used in the film. The seeds with awns last quite a while and can be activated with drops of water. Home school parents and teachers could make them a science discovery project, letting young minds learn to appreciate the wonders under their feet.

Wild storksbill plants growing in the Antelope Valley (awns visible at lower left). Photo by DFC, April 11, 2020.