Picotaur Has a Leg Up on the Competition

Swarms of tiny, insect-sized robots were once little more than fodder for cheap pulp science fiction magazine stories. But technology is finally catching up with the idea. Miniaturized electronic components and actuators, as well as new fabrication methods, are coming together to make these diminutive robots a reality. It is envisioned that swarms of these robots could quickly find victims of natural disasters in search and rescue operations, or keep close watch over bridges, buildings, and other infrastructure to look for the earliest possible sign of trouble.

There are many examples of insect-sized robots that have been developed in recent years. But by and large, they are not especially useful. While much larger robots are capable of carrying out a search and rescue operation, their pint-sized cousins are usually little more than toys. A major limitation lies in their inability to traverse difficult or varied types of terrain. They tend to be one-trick ponies, and as soon as they get out of their comfort zone they will be about as mobile as a turtle that got stuck on its back.

A trio of engineers at Carnegie Mellon University has developed a method that makes it possible to build tiny robots that are actually reasonably agile. Using their techniques, they created a 7.9 millimeter legged robot called Picotaur that can run, turn, climb stairs, push loads, and even jump. These are exactly the sort of skills a little robot needs to avoid looking like a dead cockroach the moment it runs into a little difficulty.

Picotaur was made using a cutting-edge 3D printing process called two-photon polymerization, which allows for the creation of very complex 3D structures directly on the robot's body without needing any extra assembly. These techniques have been used in the past to create 2D structures, but the creation of 3D structures is novel and could have many implications even beyond this work. This was a key to the team’s success because making such detailed and functional parts at such a small scale would otherwise be very difficult.

The researchers’ other key innovation was the unique design of the robot’s legs. By combining small and fast electrostatic actuators with a two degree of freedom leg linkage mechanism, they were able to develop an effective mode of locomotion at this miniature scale. This platform enabled Picotaur to tackle all sorts of tasks without needing any sort of reconfiguration or rewiring.

At present, Picotaur still requires a tether to supply power which is going to keep it from being used for most real-world applications. The team is exploring the possibility of using solar cells for power, which might overcome this limitation. With some refinements such as this, microbots built with the process described in this work could soon make an impact in some very important applications.