University of Washington's 1-Gram Jumping Robot Precisely Controls Jump Height

As drones increasingly buzz and hover in the sky, it is worth considering the humble jumping robot.

Jumping is a popular mode of locomotion among insects and amphibians, and it is nearly two orders of magnitude more energy-efficient than flying. Mosquitoes must constantly expend energy to stay aloft, whereas fleas only do work when they jump.

These cost savings can also pay off in the robotics world: a swarm of small, simple jumping robots could explore a site at a much lower cost than flying drones. Such robots could find gas leaks in refineries, monitor water and fertilizer use on farms, or even explore other planets.

Abandoning springs, engineers at the University of Washington created DirectHop, a robot weighing about 1 gram that can perform multiple consecutive jumps, high enough to clear a standard stair step.

The robot uses a tiny motor and three folded legs to launch itself to a specified jump height with single-centimeter precision. After landing, DirectHop can wriggle its body to flip over, ready for the next jump.

Most jumping robots mimic insects like fleas and are essentially spring-loaded. A flea compresses and then releases part of its exoskeleton, launching itself 50 times its own height.

Robots using springs and latches can also travel impressive distances, but they lack a simple way to calibrate jump distance—releasing a spring is an all-or-nothing action. Moreover, springs and latches are complex mechanical parts that are difficult to manufacture and operate at tiny scales.

DirectHop's solution is to abandon springs entirely. Senior author Sawyer Fuller says that in their design, the three hardest challenges were varying jump length, self-righting, and reloading for multiple jumps, and DirectHop overcomes all three with a completely new design.