Hummingbird Beaks Inspire Engineers To Create Stronger, More Flexible Micro Machines

Creating smaller machines is more than just shrinking their components. Macroscopic machines are intended to be compartmentalized so that the tasks are divided into small chunks and assigned to a different piece, but microscopic machines have a different design. This is because the tasks are accomplished by coordinated movement of all components to make them tough against the disorder in the microscopic world.

The Future of Micro Machine Design

At Cornell University, researchers have developed a new approach to designing complex microscale machines. They drew their inspiration from the mechanism of proteins and hummingbirds' beaks. The research was headed by Itay Griniasty and conducted at physics professor Itai Cohen's laboratory.

In a previous study, Cohen and his colleagues utilized the principles of origami in fabricating stable microscale devices. They created self-folding structures and walking robots which are innovative in size but relatively basic in function. Adding functionality to the origami sheets will turn out to be a challenging task.

According to Cohen, the machines made by the team are very, very simple, so they started thinking about increasing the functionality in highly coupled systems. They realized that every time one part of the machine is moved, all the other parts also move. This property has become a great challenge because it prevents them from isolating anything since they are all connected in the sheets.

Proteins act like a machine that hops between states in response to small changes in some parameters. The researchers got inspired by an example of this functionality at the macroscale: the hummingbird. In 2010, John F. Carr, Professor of Mechanical Engineering Andy Ruina, studied how a hummingbird's beak can be opened and closed smoothly. A mathematical idea called cusp bifurcation describes the sequence of bending and twisting the beaks by the lower jaw muscles.

Cohen and Griniasty applied this mechanism by increasing the number of states organized about a bifurcation. They tried to investigate if the increase from two to dozens or hundreds would allow the design of machines to carry out complex functions.

To answer this question, a proof-of-concept macroscale magneto-elastic model with a butterfly bifurcation was created to allow the system to transition smoothly between three stable states. To design magnetic patterns that would trigger the desired bifurcation, the researchers developed an algorithm built on dynamical systems. In the future, the team envisions demonstrating the concept at the microscale level.

Unique Characteristics of Hummingbird Beaks

Hummingbirds are one of the unique animals with exceptional characteristics. Aside from being the tiniest birds in the world, they can hover in mid-air and fly sideways and upside-down. Another remarkable feature of this animal is their beaks which have unusual shapes and functions.

At first glance, it seems like hummingbirds use their beaks to sip away at their food, but they stick their tongue into the nectar and draw it up. This means that their long needle-like beaks remain closed when feeding. Meanwhile, the beak opens when a hummingbird tries to catch insects in flight by flexing its jaws downward.

When using their beaks to draw nectars, the hummingbirds stick their tongue into the tongue and extract the sap using their two troughs. This method involves capillary action, where the nectar is pulled instead of sucked out.