Hop to It

Choosing the right robot for a job is rarely easy. Quadrupedal robots are among the most versatile, but they tend to be large and unable to fit into small spaces. Small aerial vehicles can go just about anywhere, but they are severely constrained by the amount of power they can carry onboard, which greatly limits their flight time. By making trade-offs, it is possible to find a reasonably good platform for most applications, but there are still corner cases. For instance, when the job calls for getting into small spaces and long mission times, few options exist.

A new robotics platform developed by engineers at MIT to fill this particular void has just hopped onto the scene. Their insect-scale robot can squeeze into tight spaces, and its novel form of locomotion stretches battery life far beyond what is normal for such a small machine. Rather than flying or walking, this little robot jumps. This also gives the platform the ability to punch above its weight when it comes to getting over tall obstacles and other challenging terrain.

The robot is smaller than a human thumb and weighs less than a paperclip. Despite its tiny size, it can hop about 20 centimeters — four times its own height — at speeds up to 30 centimeters per second. It accomplishes this using a compression spring “leg” combined with four flapping wing modules that help it maintain lift and orientation mid-air. The result is a hybrid approach to mobility that retains the efficiency of ground-based motion while gaining some of the versatility typically associated with flying.

By using this hybrid mode of locomotion, the robot uses 60 percent less energy than similar-sized aerial robots, enabling longer missions without the need for frequent recharging. This energy efficiency also allows the robot to carry heavier payloads — up to 10 times more than its flying counterparts. That opens the door to including onboard batteries, sensors, and processing hardware, which might make future versions of the robot capable of full autonomy in real-world environments.

The robot’s performance has been extensively tested across difficult surfaces including grass, ice, wet glass, and uneven soil. It has shown the ability to hop onto dynamically moving or inclined surfaces, such as a hovering drone or a tilting platform. Thanks to its lightweight and agile design, it can recover from collisions, perform somersaults, and continue moving across unpredictable terrain.

Currently, the robot relies on an external motion-tracking system and off-board control. But with its exceptional payload capacity and durability, the researchers believe it is well-positioned to support onboard navigation and decision-making in future iterations.

With further development, these hopping robots could play vital roles in future search and rescue missions, environmental monitoring, or any application that requires access to tight spaces or dangerous environments — all without sacrificing endurance or functionality.