Batteries have come a long way in the past few centuries, but pale in comparison to hydrocarbon fuels when it comes to energy density. When it comes to packing plenty of juice in a light, compact package, hydrocarbons are the way to go. Recently, researchers have begun to take advantage of this, powering small robots with liquid fuels. Just like Bending Unit 22, aka Bender Bending Rodriguez, this tiny robotic beetle runs on alcohol.
Affectionately named Robeetle, the tiny ‘bot weighs just 88 milligrams, comparable in mass its insectoid contemporaries. It stores methanol in a polyimide film tank, operating for up to 2 hours on a single fill. As shown in the video, a solely mechanical control system is used to actuate the robot’s legs. In the neutral state, vents in the fuel tank are open, releasing methanol vapor. This passes over nitinol muscle wires coated in a special catalyst which causes the combustion of the methanol, heating the wires. The wires then contract, moving the legs, and closing the vents. When the wire cools, the wires relax, opening the vents and beginning the cycle anew.
While the ‘bot is solely capable of walking in a single direction, it nevertheless shows the possibilities enabled by powering small devices from energy-dense fuels. Waiting for improved battery technologies to develop is such a bore, after all. We look forward to swarms of such ‘bots exploring disaster areas or performing environmental sampling in years to come. The scientific paper outlines the research outcomes in detail.
Swarms of robotic insects incapable of being swatted away may no longer be the product of science fiction and Black Mirror episodes. A team from EPFL’s School of Engineering has developed an insect propelled at 3 cm/s, dubbed the DEAnsect.
What makes this robot unique is its exceptional robustness. Two versions of the robot were initially developed, one tethered with ultra-thin wires capable of being squashed with a shoe without impacting its functions and the second fully wireless and autonomous. The robot weighs less than 1 gram and is equipped with a microcontroller and photodiodes to recognize black and white patterns.
The insect is named for its dielectric elastomer actuators (DEAs), an artificial muscle that propels it with vibrations and enables it to move lightly and quickly.
The DEAs are made of an elastomer membrane wedged between soft electrodes that are attracted to each other when a voltage is applied, compressing the membrane. The membrane returns to its original shape when the voltage is turned off. Movement is generated by switching the voltage on and off over 400 times per second. The team reduced the thickness of the membranes and developed soft, highly conductive electrodes only several molecules thick using nanofabrication techniques. They plan on fitting even more sensors and emitters to allow the insects to communicate directly with one another for greater swarm-like activity.
This may not sound like much, but previously the robots lacked the ability to break the surface tension of water. To sink, the wings need a coating of surfactant. Once submerged, the bots lack the ability to transition back from water to air. But we won’t be surprised to see that ability added as a feature while the scope of the project continues to creep. So yes, you can jump into water to escape bees but not to escape Robobees.
Diving isn’t the only wonder to behold. The ‘head’ of the RoboBee is utterly fascinating. It’s constructed by folding the PCB into a pyramid like structure, 4 sides of the head include a photo-transistor covered by a diffused lens which the bot uses for self positioning by sensing changes between the bright light of the sky and absence thereof below the horizon. This concept is taken directly from biological self-righting systems found on the head of most insects, however Harvard’s version has one more sensor than the stock 3 seen on insects. Take that, nature!
It’s name is Blaberus Cranifer, or Death’s Head for short. Light has now been shed on this once secret project built by the Immanuel Kant Baltic Federal University for a “vague” Russian organization. The little guy has a 20 minute battery life and can carry a 10 gram payload. Which comes in handy when you want to sneak a camera into hard to reach places. Other requirements were for it to look and behave like a real live insect.
It’s an impressive project considering it was built from scratch in only seven months time. Its intricate gears and other mechanical features would require the hands of a skilled watch maker to construct. Alternatively, one can control live insects such as controlling a roach’s brain or hooking up some radio controls to a live beetle. But building robotic insects is still pretty cool.
Be sure to check out the well made video detailing some of the project’s build process.