A team of mechanical engineers from Cornell University, in collaboration with a colleague from Technion-Israel Institute of Technology, have created a miniature robot that is powered by a combustion engine. This innovative design deviates from the traditional battery-powered approach commonly used in small robots. The researchers published their findings in the journal Science, outlining the construction of the tiny engine and potential applications for its use. Ryan Truby, from Northwestern University, provided a perspective piece in the same journal issue, further exploring the team’s work.

As robotic technology continues to advance and miniaturize, powering small robots becomes increasingly challenging with conventional battery technology. To overcome this limitation, the research team turned to an internal combustion engine, an age-old technology that harnesses controlled explosions to generate mechanical motion. Instead of using gasoline, the researchers utilized methane vapor and oxygen to create a compact combustion engine capable of powering a miniature robot.

The construction of the engine involved the development of a small combustion chamber along with a sparking agent to initiate controlled explosions. The resulting force from each explosion propelled the piston-like top of the chamber upward. Testing demonstrated that the piston could exert a force of 9.5 newtons. To facilitate continuous motion, the researchers designed a pump that worked in conjunction with the igniter, enabling the piston to oscillate up and down approximately 100 times per second.

In addition to constructing a single engine, the team built a second engine identical to the first and connected both to serve as feet and legs for a tiny frog-shaped robot. By synchronizing the firing of the engines, the robot was able to jump. Alternatively, by alternating the firing pattern of the engines, the robot could walk.

Although the engines are currently small enough to fit four on the face of a penny, further miniaturization is required for certain components, such as the fuel system and holding tank, as well as the power source for the spark generator. Nevertheless, the researchers propose that their design holds potential for the development of various types of miniature robots.

Overall, this groundbreaking research represents a significant advancement in the field of robotics, showcasing the potential for utilizing combustion engines on a tiny scale.

Source:

Cameron A. Aubin et al. 2023. “Powerful, soft combustion actuators for insect-scale robots.” Science. DOI: 10.1126/science.adg5067.

Ryan L. Truby. 2023. “Chemically fueling new microrobot abilities.” Science. DOI: 10.1126/science.adk0522.