The tear-shaped soft robot developed at North Carolina State University continues to jump without needing to reset between hops as long as it is illuminated by infrared light.
It is said this self-resetting motion originates from a mechanism that stores elastic energy by twisting and then releases it all at once.
Ji Yin, the corresponding author of this study and a professor of mechanical and aerospace engineering at the university, says the design of this "ring jumper" is very simple and uses twist to store elastic energy; the energy is released at once and therefore the robot does not need to reset between jumps and resets itself.
Accordingly, the robot is made from a tear-shaped liquid crystal elastomer strip with a thin V-shaped aluminum tube attached to one end. Infrared light causes contraction on the surface of the strip and its rotation; the stiff V-shaped head prevents simple rolling and progressively twists the strip further until the energy reaches a critical point and, when released suddenly, launches the robot into the air.
According to ITNA and citing SciTechDaily, Fengji Chi, the first author of the study, adds that by changing the angle of the V-shaped head the type of motion can be controlled; an angle of 120 degrees causes crawling, 90 degrees produces forward jumping, and 50 degrees yields vertical jumping.
It is worth noting these robots succeeded in experiments in traversing slopes and obstacles and moving on grass, sand, rock, and leaf litter.