Creating cutting-edge robots requires a unique mix of elements: time, technical expertise, and the right materials. Now, researchers at Cornell University have incorporated a rather unconventional component into their robot designs – fungal mycelia sourced from the forest floor.
By tapping into the natural electrical signals of mycelia, these researchers have pioneered a novel method for controlling “biohybrid” robots. This breakthrough holds the promise of enabling robots to adapt and respond to their environment in ways that surpass traditional synthetic models.
“This paper is the first of many that will use the fungal kingdom to provide environmental sensing and command signals to robots to improve their levels of autonomy,” said Rob Shepherd, professor of mechanical and aerospace engineering at Cornell Engineering and the paper’s senior author. “By growing mycelium into the electronics of a robot, we were able to allow the biohybrid machine to sense and respond to the environment. In this case, we used light as the input, but in the future, it will be chemical. The potential for future robots could be to sense soil chemistry in row crops and decide when to add more fertilizer, for example, perhaps mitigating downstream effects of agriculture like harmful algal blooms.”
When envisioning future robots, engineers have drawn inspiration from the animal kingdom, creating machines that replicate the movements, sensory abilities, and even temperature regulation of living organisms. Some robots have even integrated living material, such as muscle tissue cells, yet maintaining the health and functionality of these complex biological systems poses challenges.
Nevertheless, mycelia, the underground vegetative part of mushrooms, offers numerous benefits. They can thrive in harsh environments and possess the capability to detect and respond to chemical and biological signals from various sources.
“If you think about a synthetic system – let’s say, any passive sensor – we just use it for one purpose. But living systems respond to touch, they respond to light, they respond to heat, they respond to even some unknowns, like signals,” lead author Anand Mishra said. “That’s why we think, OK, if you wanted to build future robots, how can they work in an unexpected environment? We can leverage these living systems, and any unknown input comes in, the robot will respond to that.”
Integrating mushrooms and robots is a multidisciplinary endeavor that requires expertise in mechanical engineering, electronics, mycology, neurobiology, and signal processing. This unique combination of skills is essential in developing such complex systems.
“You have to have a background in mechanical engineering, electronics, some mycology, some neurobiology, some kind of signal processing,” Mishra said. “All these fields come together to build this kind of system.”
Mishra’s collaboration with interdisciplinary researchers, including Bruce Johnson and Kathie Hodge, highlights the diverse expertise necessary for this innovative work. Learning to record electrical signals in mycelia membranes and grow clean mycelia cultures demonstrates the intricate challenges involved in this groundbreaking research.
The system developed by Mishra has revolutionized the field by incorporating an electrical interface that effectively blocks out vibration and electromagnetic interference. This allows for the accurate recording and processing of mycelia’s electrophysiological activity in real-time. The system also includes a controller inspired by central pattern generators – a type of neural circuit. Essentially, the system reads the raw electrical signal, processes it, identifies the mycelia’s rhythmic spikes, and then converts this information into a digital control signal, which is sent to the robot’s actuators.
This groundbreaking system has led to the creation of two biohybrid robots: a soft robot resembling a spider and a wheeled bot. These robots successfully completed three experiments. In the first experiment, the robots walked and rolled in direct response to the natural continuous spikes in the mycelia’s signal.
In the next experiment, the robots were stimulated with ultraviolet light, leading to a change in their gaits, demonstrating mycelia’s remarkable ability to react to their environment. Finally, in the third scenario, the researchers were able to override the mycelia’s native signal entirely.
The implications of Mishra’s work extend far beyond the fields of robotics and fungi, showcasing the potential for groundbreaking advancements in various scientific domains.
“This kind of project is not just about controlling a robot,” Mishra said. “It is also about creating a true connection with the living system. Because once you hear the signal, you also understand what’s going on. Maybe that signal is coming from some kind of stress. So you’re seeing the physical response because those signals we can’t visualize, but the robot is making a visualization.”
Journal reference:
- Anand Kumar Mishra, Jaeseok Kim, Hannah Baghdadi, Bruce R. Johnson, Kathie T. Hodge, Robert F. Shepherd. Sensorimotor control of robots mediated by electrophysiological measurements of fungal mycelia. Science Robotics, 2024; DOI: 10.1126/scirobotics.adk8019