Imagen-Micro Robotics Revolution: How Tiny Machines Are Solving Giant Problems

Introduction

In a world where technology continues to shrink in size but grow in capability, a revolution is quietly taking place in robotics labs around the globe. The "Veritasium" podcast, hosted by Derek Muller with his guest Henry Reich, recently took listeners on a fascinating journey into the cutting-edge field of micro robotics - where robots the size of insects are performing extraordinary feats that could one day revolutionize everything from disaster response to medical care.

The episode featured unprecedented access to some of the world's foremost micro robotics labs, showcasing remarkable innovations that blur the line between science fiction and reality. These tiny robots can fly like bees, jump like fleas, swim underwater, and even run on vertical surfaces - all while weighing less than a few Cheerios.

Why does this matter? As our world faces increasingly complex challenges - from navigating disaster zones to performing delicate medical procedures - these miniature machines offer solutions that their larger counterparts cannot. They can access spaces too small or dangerous for humans or conventional robots, potentially saving lives in collapsed buildings or inspecting critical infrastructure without shutting it down.

In this blog post, we'll explore the fascinating science behind these micro robots, their potential applications, and the unique challenges their creators face when engineering at such tiny scales.

The Physics of Being Small: Why Size Changes Everything

One of the most fascinating aspects of micro robotics is how differently physics behaves at smaller scales. Derek Muller explained this fundamental principle through a simple but illuminating example:

"Larger objects typically have less surface area relative to their volume, and that's important," he noted. "Let's just approximate a flyer by a cube. Let's say it's 10 centimeters on a side. Well then that would have a volume of 10 by 10 by 10, or a thousand cubic centimeters, and it would have an area of 10 by 10 by six sides, 600 square centimeters. So the surface area to volume ratio would be 0.6 to one."

He then contrasted this with a much smaller object: "But now imagine we have a much smaller flyer that is just one cubic centimeter in volume. Well, its surface area is going to be one by one times six. That is six square centimeters. So that's gonna be 10 times the surface area to volume ratio."

This seemingly abstract mathematical relationship has profound implications for how small robots must be designed. As Derek explained, "Drag depends on surface area. So if you have more surface area to volume, well you're gonna have a lot more drag, and also, at that small scale, you'll be much lighter relative to that drag. So you're not gonna have as much inertia, so you'll get pushed around more by the air, so you can't just soar through it like a bird."

This is why insects and micro robots must flap their wings hundreds of times per second rather than gliding like birds - they're generating complex air vortices that create lift in an entirely different way.

Breaking the Surface Tension Barrier

Perhaps one of the most remarkable innovations covered in the podcast was a tiny submarine-like robot that can both swim underwater and fly in air - a transition that proves incredibly challenging at the micro scale.

"That's a consequence of physics at a smaller scale," explained Dr. Kevin Chen from MIT. "The surface tension is like a wall that blocks the transition process."

Surface tension occurs because water molecules are slightly polar. At the surface, where there's no water above, the pull is only sideways and downwards, creating strong cohesive forces that compress the surface into a tightly packed layer - difficult to break through, especially for something as tiny as these robots.

The submarine robot ingeniously overcomes this challenge through a multi-step process:

1. It splits water into hydrogen and oxygen gases
2. Stores these gases in a buoyancy chamber
3. Uses the buoyancy to bring its fragile wings to the surface
4. Ignites the gas with a spark, creating a mini-explosion
5. The explosion breaks the surface tension, launching the robot 30cm into the air

Another robot demonstrated a completely different approach to the same problem. This one uses large water-repellent copper pads on its feet to walk on water, much like a water strider. When it needs to dive beneath the surface, it applies 600 volts to those pads, creating a positive charge that attracts water molecules, effectively breaking the hydrophobic barrier and allowing the robot to sink on command.

Both solutions represent the kind of creative problem-solving that makes micro robotics such a fascinating field - engineers must often reimagine the very fundamentals of locomotion when working at this scale.

Flying at Insect Scale: RoboBees and Beyond

The podcast took listeners inside Kevin Chen's MIT lab - one of the only places in the world where robots as small as insects attempt flight. These "RoboBees" demonstrate extraordinary capabilities but require equally extraordinary engineering.

"Components have to be precise to within five microns," Derek noted. "That's a tenth the width of a human hair."

The researchers shared a humorous moment about their work: "In the summer, we have those very big flies zipping by in the lab, and I was making the statement of, 'Oh, they're just showing off,'" joked Dr. Chen, highlighting the humbling experience of trying to replicate what insects do naturally.

These tiny flying robots use different mechanisms than their larger counterparts. The first generation of RoboBees relied on piezoelectric crystals - special materials that contract slightly when voltage is applied across them. However, these crystals have a significant limitation: they're extremely fragile. Even a small impact to the wings can crack the crystal, rendering the robot useless.

MIT's newer approach replaces these crystals with soft polymers coated with carbon nanotubes on each side, creating something akin to artificial muscles:

"They take a polymer and they coat each side with carbon nanotubes that creates two effective conducting plates," Derek explained. "If you apply opposite charges to these plates, that pulls them together, stretching out the polymer. But if like charges are applied to both plates, they repel, and so the polymer shrinks."

This innovation makes the robots significantly more durable - they can take bumps and scrapes and keep working. Even more remarkably, these artificial muscles can self-heal if damaged:

"When high current is cycled, the carbon nanotubes that are touching burn off and so the muscle self-heals," Derek noted. The MIT team even developed laser surgery techniques for these robots, further extending their resilience.

Energy Conservation: The Challenge of Power

One of the most significant challenges for micro robots is power. At such a small scale, there's simply no room for large batteries, and as batteries are scaled down, they become increasingly inefficient.

"Batteries need shielding to prevent damage, short circuits, and leaks," Derek explained. "As batteries are scaled down, this shielding has to stay about the same thickness. So that means smaller batteries become increasingly inefficient."

This challenge has led to creative solutions. One RoboBee conserves energy by hopping rather than flying continuously:

"Normally this drone can only fly continuously for 6.3 minutes, but with the hopping attachment, it can keep moving for 50 minutes, nearly 10 times longer," noted Derek. This approach could be particularly effective in environments with low gravity and low air resistance - like Mars.

The Penny-Sized Combustion Engine

Perhaps the most surprising innovation featured in the podcast was Cameron's penny-sized internal combustion engine - effectively bypassing the limitations of batteries altogether:

"We just said, let's just sail past all of that and just use a video game cheat code and just power our robot with the smallest explosions possible and put two tiny internal combustion engines on board it, and it works," Cameron explained with palpable enthusiasm.

This miniature marvel runs on a continuous stream of methane and oxygen, which is ignited in a chamber. The resulting combustion creates a burst of energy that pushes against a flexible polymer membrane acting as a piston:

"The membrane moves as the piston and then instead of having to, like, have any sort of elaborate system that brings it back down because it just naturally is elastic, it sort of has its own restoring force. That was our clever little innovation," Cameron explained.

Remarkably, despite the continuous flow of flammable gases, the fuel line never catches fire - another example of how physics changes at smaller scales. As explosions get smaller, they lose heat more quickly to their surroundings, preventing the flame from traveling back up the fuel line.

The power-to-weight ratio of this approach is truly impressive. As Cameron noted, "It weighs 1.6 grams, which is about as much as a gummy bear weighs. It can jump like two feet in the air approximately. It can carry 22 times its body weight, which is about what a cockroach or a lot of beetles can do."

Real-World Applications: From Disaster Response to Engine Inspection

While much of the research in micro robotics remains experimental, the podcast highlighted several promising applications already being developed:

Engine Inspection

Every day, planes complete hundreds of thousands of flights, most with multiple turbine engines that must be regularly inspected for cracks. Traditional inspections are expensive and time-consuming:

"Manufacturers inspect them every 3000 flight cycles or 180 days, but inspections cost tens of thousands of dollars and can take a whole day," Derek explained.

This is where the cockroach-inspired robot HAMR (Harvard Ambulatory MicroRobot) comes in. It's incredibly fast - running 10.5 body lengths per second, faster than a horse in relative terms. Its special foot pads can apply voltage to metal surfaces, creating an adhesive effect that lets it stick to and climb metal surfaces - even upside down.

Rolls-Royce and Harvard are working to deploy HAMR inside engines to inspect for turbine cracks, potentially saving time and money while improving safety.

Disaster Response

The podcast also discussed how micro robots could transform disaster response. During 9/11, robots were deployed in the search for survivors at Ground Zero, but they proved ineffective - they were too big, expensive, and prone to getting stuck.

Micro robots address these limitations. They can navigate tight spaces, withstand damage and debris, operate across varied environments, and are inexpensive enough to be replaceable if destroyed:

"The material cost is actually quite low for making the robot. The human labor is high, but in terms of the material, right, couple of dollars per robot," explained Dr. Chen.

The vision is to deploy swarms of these tiny robots to search for survivors in disaster zones - something that would have been science fiction just a few decades ago.

Ethical Considerations: The "Black Mirror" Question

No discussion of tiny robots would be complete without addressing the ethical implications. The podcast didn't shy away from these concerns, with Derek directly referencing popular culture:

"I understand when I say swarm, you might get a little worried. I mean, swarms of miniature killer robots are straight out of dystopian sci-fi. Think the hunter-seeker from 'Dune' or the killer robot bees from 'Black Mirror.'"

Dr. Chen acknowledged this concern with good humor: "When that came out, everybody that I had ever met in my entire life sent me a text message and was like, 'Hey bro, you seen this?'"

The initial RoboBee project was actually started with the goal of replacing dying bee populations during the colony collapse disorder crisis of the early 2000s. However, the researchers quickly realized this wasn't practical or desirable:

"Bees can do much better jobs in terms of pollination than those robots much more cheaply," Dr. Chen pointed out. "From an environmental protection perspective, I think it doesn't make sense to replace bees with robotics bees... if you have so much money, why you making those bees than protecting the real bees."

When asked about the potential for surveillance applications, Dr. Chen offered a thoughtful response:

"We really focus on the fundamental science and solving the fun technical problems. And as a society in general, we all should think about collectively how to prevent those new technology from doing harm."

The Future: From Tethered Prototypes to Autonomous Swarms

Currently, most of these micro robots remain tethered to external power sources and computing systems:

"We have offboard sensing from those cameras, you have offboard power from those, and offboard computation. What you see today is everything is offboard," Dr. Chen explained. "But hopefully in five years, then we can combine both sensing autonomy and power autonomy, and that's the longer-term goal."

Harvard's RoboBee has already managed short bursts of untethered autonomous flight, suggesting we aren't far from seeing truly independent micro robots operating in the world around us.

For the scientists involved, however, the work goes beyond practical applications. As Dr. Chen put it:

"If it's about application, we should all like make a startup and try to like think about what we can do to make money, right? We think there are nice applications, like inspection and search and rescue, but I would say as a research lab, we are mostly driven by curiosity. I think that's a very honest answer."

Conclusion

The world of micro robotics represents one of the most exciting frontiers in engineering and robotics today. By working at the insect scale, scientists are not only creating machines that can perform remarkable feats but also deepening our understanding of the very physics that governs our world.

These tiny robots challenge us to think differently about what's possible. They demonstrate that sometimes the most powerful innovations come in the smallest packages. From disaster zones to medical applications, engine inspection to environmental monitoring, micro robots have the potential to transform countless fields by accessing spaces and performing tasks that were previously impossible.

As we look to the future, the question isn't whether micro robots will become part of our world, but how we'll harness their capabilities responsibly. With researchers like Dr. Chen focused on both innovation and ethical considerations, there's reason to be optimistic about the tiny technological revolution unfolding in labs around the world.

Key Points

1. Scale changes physics: Micro robots face entirely different physical challenges than larger machines, requiring innovative approaches to flight, movement, and power generation.
2. Surface tension barrier: For robots that transition between air and water, surface tension creates a significant obstacle that requires creative engineering solutions like gas-powered explosions or electrically charged feet.
3. Power limitations: Traditional batteries become increasingly inefficient at smaller scales, leading to innovations like hopping locomotion and miniature combustion engines.
4. Artificial muscles: New soft polymer materials coated with carbon nanotubes can act as artificial muscles, allowing for more durable and even self-healing robots.
5. Real-world applications: From inspecting jet engines to searching disaster zones, micro robots offer practical solutions to problems that larger machines can't address.
6. Ethical considerations: While there are legitimate concerns about surveillance applications, researchers are primarily focused on beneficial uses and open societal discussion about risks.
7. Future autonomy: Current micro robots often rely on external power and computing, but fully autonomous versions are likely just years away.

For the full conversation, watch the video here.