Walking robots can step right off the 3D-printer - powered by air

In the world of robotics, the dominant image has always been a machine filled with wires, chips, and rigid joints. Today, that image is being replaced by something more flexible – literally.

Engineers at the Bioinspired Robotics Laboratory at the University of California San Diego have developed a new kind of robot that can walk without electronics.

It doesn’t rely on electronics or rigid parts. It doesn’t even need to be assembled from multiple materials. You can print it in one go, using only one type of soft filament and a standard desktop 3D-printer. Add a simple cartridge of compressed gas, and the robot walks.

This innovation represents a huge shift in how machines are built and imagined. For the first time, robots can be made quickly, cheaply, and almost anywhere. They can function where electronics fail and can be deployed in extreme environments, all without the need for metal skeletons or batteries.

3D-printed robots walk on air

The researchers behind this project deliberately avoided complexity. Instead of using expensive tools or rare materials, they used a desktop printer and a common printing filament. Their goal was to make walking robots as accessible as possible. The result? A complete, functioning robot for just $20.

“This is a completely different way of looking at building machines,” said Michael Tolley, a professor in the UC San Diego Department of Mechanical and Aerospace Engineering and the paper’s senior author.

The robot they developed doesn’t need circuits to walk. A cartridge of compressed gas feeds pressure into soft structures within the robot’s body.

This air-driven motion replaces motors and wires. It’s a minimalistic approach that opens the door to robots in places where conventional electronics simply can’t go.

Why a soft robot matters

In many high-risk environments – like radioactive zones, disaster sites, or deep space – electronics often fail. They short out, overheat, or get damaged. That’s where these soft robots shine. Because they contain no metal parts or circuits, they resist extreme conditions naturally.

The UC San Diego team tested the robots both in the lab and outdoors. Indoors, the robots walked for three full days without stopping. The only requirement was a steady supply of compressed gas.

Outside, the robot ran on a small gas cartridge and proved it could traverse rough terrain. It walked over sand, grass, and even underwater. Its flexible limbs adapted to different surfaces with ease.

This adaptability, combined with low production cost, makes these robots ideal for emergency response and exploration missions. They don’t break easily. They don’t rely on fragile parts. And they can be printed on demand.

Soft robot in one single print

The material used to make these robots is nothing special – just regular 3D-printing filament.

What makes it special is how it’s used. The team created a system where every part of the robot, including the muscles and controller, is made from the same soft material in one print. That means no assembly.

“These robots are not manufactured with any of the traditional, rigid components researchers typically use,” Tolley said.

Instead of motors, the robot has soft actuators. These are inflated and deflated using air pressure, giving the robot its walking motion. The engineers designed everything to work in harmony, using only softness and air.

This design breaks away from decades of engineering tradition. It’s not just an experiment. It’s a functioning machine that reimagines what robotics can be.

How the robot walks

Walking might seem simple, but coordinating movement in a robot is complex. Without electronics, the UC San Diego team turned to pneumatics. They built a soft oscillating circuit that mimics the old-school steam engine.

To move the robot’s six legs, the circuit alternates air pressure between two sets of three legs. This rhythmic action creates forward movement. The legs move in four directions – up, down, forward, and backward – giving the robot balanced control. It can walk in a straight line, even on uneven ground.

“We have taken a giant leap forward with a robot that walks entirely on its own,” said Yichen Zhai, the lead postdoctoral scholar behind the build.

What sets this apart is that the entire control system is also soft. There’s no need for chips or code. The robot responds only to changes in air pressure, like a living system without a nervous system.

Pushing toward a greener future

The team isn’t stopping at walking. Their next goal is to make the robots self-contained. That means finding a way to store the compressed gas inside the robot’s body. Doing so would make these robots fully untethered.

The experts are also exploring sustainable materials. Using recyclable or biodegradable filaments would reduce the robots’ environmental impact. This makes them even more attractive for short-term use in hazardous areas, where retrieval may be impossible.

Another major step involves adding manipulators. Arms, grippers, and other tools would give the robots the ability to interact with their surroundings – pick up debris, press buttons, or even rescue objects or organisms.

From lab to real-world testing

Building this robot required partnerships. The team worked closely with BASF through their California Research Alliance (CARA). BASF helped test different soft materials that could be printed using standard 3D-printers.

Some of the more advanced materials aren’t yet available to the public, but the researchers successfully built working robots using common options as well.

Funding from the National Science Foundation supported the project. That support helped push the team toward practical testing, real-world application, and wider dissemination.

Before publishing their findings, the team completed their first walking robot in 2022. They showcased it at the Gordon Research Conference on Robotics that same year.

That early demonstration proved the technology could move beyond the lab and into broader discussions on the future of machine design.

A new chapter in robotics

The quiet hum of a 3D-printer now builds machines that walk, explore, and survive without wires.

The team at UC San Diego has shown that the future of robotics might not be harder, faster, or more complex. Instead, it might be softer, simpler, and more adaptable.

By printing machines that rely only on air and softness, they’ve introduced a new chapter in robotics. One where simplicity leads, and where machines don’t just look alive – but move like it too.

The study is published in the journal Advanced Intelligent Systems.

Image Credit: David Baillot/University of California San Diego

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