Robotics
3D-printed robot walks without electronics
The machine is powered entirely by a cartridge of compressed gas and can be printed in one piece using a single material.
A robot has been developed that can walk without electronics, powered solely by a cartridge of compressed gas. Designed by researchers at the Bioinspired Robotics Laboratory at the University of California San Diego, the machine is 3D-printed in a single process using one material.
The researchers used a desktop 3D printer and a standard printing material, resulting in a robust and low-cost design, with each robot costing approximately $20 to produce. This work is published in an advance online edition of Advanced Intelligent Systems.
“This is a completely different way of looking at building machines,” says the paper’s senior author Michael Tolley, a professor of mechanical and aerospace engineering at UC San Diego.
The robots are designed for use in environments where electronics are unsuitable, such as areas with high radiation, disaster zones, or space exploration. Laboratory tests demonstrated that the robots could operate continuously for three days when connected to a steady supply of air or gas.
The researchers showed that the robots could walk untethered outdoors using a compressed gas cartridge, successfully traversing surfaces such as turf and sand, and functioning underwater. The goal was to create robots that could walk immediately after printing, powered by air, while being made from flexible, soft materials.
“These robots are not manufactured with any of the traditional, rigid components researchers typically use,” says Tolley. Instead, they are made of simple 3D-printing filament.
The main challenge was developing a design that integrated artificial muscles and a control system, all made from the same soft material in a single print. The team, led by postdoctoral scholar Yichen Zhai in Tolley’s research group at the UC San Diego Jacobs School of Engineering, adapted a 3D printing technique that they used previously to build an electronics-free gripper.
Their efforts led to the fabrication of a six-legged robot. Zhai says: “We have taken a giant leap forward with a robot that walks entirely on its own.”
Yichen Zhai and the robot. Photo courtesy David Baillot/University of California San Diego.
To enable movement, the team developed a pneumatic oscillating circuit that controls the repeated motion of soft actuators, using a mechanism similar to that of a steam locomotive.
This circuit coordinates the six legs by alternating air pressure between two sets of three, allowing the robot to walk. Each leg can move in four degrees of freedom – up, down, forward, and backward – enabling the robot to travel in a straight line.
Next steps for the project include developing methods to store compressed gas within the robots and exploring the use of recyclable or biodegradable materials. The researchers are also investigating the integration of manipulators, such as grippers.
Tolley’s lab collaborated with BASF through the California Research Alliance (CARA) to test various soft materials suitable for use with standard 3D printers. While some high-end materials tested are not commercially available, the team was able to print functional robots using off-the-shelf options.
The research was partially funded by the National Science Foundation. The team completed the 3D-printed walking robot in 2022 and presented it at that year’s Gordon Research Conference on Robotics.
* Read the research article, ‘Monolithic Desktop Digital Fabrication of Autonomous Walking Robots’, here.
