The researchers from Cornell University’s Organic Robotics Lab have developed a tiny combustion engine that gives a frog-like robot the ability to make explosive leaps and have fine movement control. Unlike most robots that use electric actuators, this robot runs on energy-dense chemical fuels, allowing for greater performance. The combustion engine is about 5mm in diameter and operates similarly to a regular combustion engine. It accepts methane and oxygen into a combustion chamber and ignites it with a spark. The combustion chamber is covered with a highly elastic silicone Dragon Skin membrane, which acts like a piston in a car engine, expanding as the fuel burns and quickly recovering to push out exhaust gases through small vents.
These mini combustion actuators can handle forces greater than 9.5N and operate at frequencies over 100 cycles per second. The researchers embedded 3D-printed prototypes of these actuators in a tiny frog robot’s foot pads. By controlling the spark frequency, fuel equivalence ratio, and fuel flow, they were able to make the robot crawl, hop, rotate, and jump up to 1.8 feet in the air. The robot was able to move on different surfaces, carry cargo weighing 22 times its own body weight, and still maintain control over its movements.
These combustion actuators offer roboticists an alternative when quick and explosive movements are required. They provide an extra option for robots that may need assistance with leg hydraulics or require the ability to deliver powerful and fast movements. The research was published in the journal Science.
– IEEE Spectrum