Mushroom-Powered Robots Take a Trip

Robots have a well-earned reputation for being big lumbering machines that, try as they might, cannot help but be awkward and a bit clumsy. This view of robots is expressed casually in daily life when we say that someone is acting robotic, which means they are behaving in an unusual, stiff, unemotional, and nonhuman sort of way. And have you ever seen someone on the dance floor doing the robot dance?

This is not just a matter of robots being kind of weird that we can laugh off, however. It is a real problem when it comes to designing applications in which robots are expected to mimic actions typically carried out by a person. This issue also makes things awkward where human-robot interactions are involved.

In order to create more human-like robots, researchers have increasingly turned to tools like machine learning to better mimic the capabilities and movements of humans. These efforts have gone a long way toward achieving the goal, yet we are still not all the way there yet. This has led some to hold the view that artificial neural networks may simply not be as good of a fit for the job as their natural counterparts.

To test that theory, many research projects have attempted to create biohybrid robots that incorporate living tissue into otherwise mechanical systems to give them better sensing and decision-making abilities. This nascent field is still having trouble getting off the ground, however, in large part because of the difficulty of keeping living tissue alive and well under these conditions. But now there may be hope on the horizon as a team at Cornell University has developed a more practical type of biohybrid robot.

A fungus among us

Rather than depending on muscle or neural tissue, as most previous research in the area has, the team worked with fungal mycelia — the part of mushrooms that remains underground. Fungal mycelia is very hardy and can grow even under harsh conditions. It can also sense a diverse array of biological and chemical signals, which make it interesting from the perspective of robot control systems.

In this case, the researchers allowed the fungal mycelia to grow into the electronics of a robot. In this way, traditional electronics components can receive and interpret the electrical signals that they produce. Those signals can then be leveraged to sense and respond to the environment. While the organism can respond to many conditions, the team focused on reactions to light in this proof of concept.

A pair of biohybrid robots were built to test this approach — a wheeled robot, and another that resembles a spider (yuck, mushrooms and spiders?). It was demonstrated that by shining light on the fungus, the spider robot could be made to walk. Further, by directing ultraviolet light at the organism, the walking gait of the robot could be altered.

This may be a relatively simple first step, but it could ultimately have a meaningful impact on the field, allowing us to design systems with more human-like sensing and response capabilities. In the near future, the researchers envision applications for their technology in agriculture, where biohybrid robots might sense complex changes in soil chemistry and decide how much fertilizer to apply.