A team of mechanical engineers at Cornell University, in collaboration with a colleague from Technion-Israel Institute of Technology, has developed a groundbreaking tiny robot that is powered by a combustion engine. This innovative design opens up new possibilities for the miniaturization and powering of robots.
Traditionally, most miniature robots have been battery-powered. However, as technology advances and robots become smaller and more complex, it becomes increasingly challenging to provide them with sufficient power using conventional battery technology. In response to this challenge, the researchers turned to an ancient technology—an internal combustion engine.
An internal combustion engine utilizes the force generated by controlled explosions to move a part, such as a piston in a car engine. By harnessing the power of repeated explosions, the engine creates a continuous force that propels a vehicle. The research team successfully adapted this concept to create a tiny combustion engine that runs on methane vapor and oxygen, rather than gasoline, to power a micro robot.
To build the engine, the researchers constructed a miniature combustion chamber and incorporated a sparking agent to initiate the explosion. When the explosion occurs, the top of the chamber is pushed upward, similar to the movement of a piston in a car engine. The team achieved impressive results during testing, with the piston exerting a force of 9.5 newtons. Additionally, they developed a pump that synchronized with the igniter, enabling the piston to move up and down at a rate of approximately 100 times per second.
In an exciting development, the team used two identical engines as the feet and legs of a frog-shaped robot. By firing the engines simultaneously, the robot could jump, while alternating firing produced a walking motion. The researchers note that each engine weighs just 325 milligrams and could fit four of them on the face of a penny. Although some components, such as the fuel system and power source, still require miniaturization, the team envisions their combustion engine design being applicable to a wide range of tiny robots.
The potential applications of this breakthrough are vast, with implications for fields such as microsurgery, environmental monitoring, and even space exploration. This achievement represents a significant step forward in the quest to develop highly capable miniaturized robots.
– Cameron A. Aubin et al, Powerful, soft combustion actuators for insect-scale robots, Science (2023). DOI: 10.1126/science.adg5067
– Ryan L. Truby, Chemically fueling new microrobot abilities, Science (2023). DOI: 10.1126/science.adk0522