Researchers create cyborg cockroaches that carry their own energy packs

Ever thought you’d see a cyborg cockroach running on solar power and carrying a backpack that looks like an electrical circuit? A research team from Japan’s RIKEN Research Institute has transformed a normal Madagascar hissing cockroach into a real cyborg insect by connecting a lithium battery, a solar cell, several wires and a tiny electronic circuit. The cyborg can be controlled via Bluetooth signals, and the researchers suggest such robo-bugs could be used for search and rescue missions in the future.

The researchers call their cyborg an insect-computer hybrid system that contains a living insect as a platform and a mini electronic system as a controller. Basically, it’s a biobot that can be piloted like a robot, but it has the ability to explore and navigate a complex environment with the proficiency of an insect. The researchers claim that insect cyborgs could even beat traditional soft robots when it comes to meaningfully navigating the real world.

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Taking into account the body shape of the 6 cm long cockroach, the researchers designed a polymer backpack that could carry all the electronic equipment without disturbing the insect when it moved. The backpack carried an electronic controller, a lithium battery, and several wires. Each wire was connected to the controller on one side and to different legs of the cockroach on the other.

Whenever the researchers want the cockroach to move, they send a Bluetooth signal to the circuit board, which sends electrical current down the wires to its legs. These currents mimic sensory inputs that cause the cockroach to move left or right, taking advantage of reflexive behavior. The cockroach’s brain is still needed to activate its muscles and get the cockroach to move.

However, researchers soon realized that a cyborg insect might need to function for many days or even weeks. The tiny lithium battery won’t be enough to meet energy needs for that long, and since the cockroach’s brain is intact, it can abandon whatever mission it’s been sent on and run away.

To increase energy supply, an ultra-thin solar cell was created and planted on the cockroach’s abdomen to solve this problem. Despite being only 4 x 10⁻³ mm thick, the solar cell delivered 50 times the power required for the control unit. Unfortunately, it was wide enough to impede the cockroach’s movement. During initial testing, the researchers found that the insect was moving at half its original speed and failed to return to its normal orientation each time it turned or fell.

The researchers made some adjustments to the cell’s position and arrangement, and eventually they were able to outfit the cyborg cockroach with a solar cell and battery that delivered 17.2 mW of power.

While further explaining the importance of the solar cell assembly, researchers and one of the study’s authors, Kenjiro Fukuda, told Ars Technica, “To accomplish the urban rescue task, cyborg insects contain computers to control locomotion and sensors to search.” [for] people and wireless communication devices. These require 10-100 mW total power consumption. Therefore, energy harvesting devices attached to the insects are crucial to increase the range of action and functionality of biobots.”

He also said that other scientists have proposed additional types of biorobots, ranging from moth robots to cyborg beetles. However, most of these cyborg insects lack energy-gathering devices on their bodies, as the area and loading of the harvesting device severely limit their mobility. Therefore, adding a suitable energy-harvesting device (the solar cell) to charge a cyborg insect’s electronic control unit was one of the key achievements of their research.

Cyborgs vs Soft Robots

It might seem more practical and easier to use soft robots instead of cyborg insects for search and rescue missions. Soft robots would never abandon the mission like cyborg cockroaches; moreover, they can be made faster and more efficient. Then why do we need cyborg insects? The answer is energy and cost – to turn a cockroach into a cyborg, all we need is a miniature circuit, a power source, some wires, a controller and a polymer backpack. A soft robot is created completely from scratch.

Although connecting the wires to a cockroach’s legs may seem time-consuming, it takes more time to build a soft robot. In addition, such robots have high energy requirements compared to their insect counterparts. “We control insect locomotion by sending electrical signals to sensory nerves. This approach requires a power consumption of ~100uW, which is much lower than the required power consumption of movable actuators for small robots (typically 100mW or more),” Fukuda said.

Aside from having robotic abilities, a cyborg cockroach navigates an environment using the input it receives from its natural senses. This is something a soft robot can never achieve, and that’s why the researchers argue that cyborg insects could provide better assistance in search-and-rescue missions compared to any other technology. Fukuda and his team are now planning to create cyborg versions of other insect species, including ones that can fly.

npj Flexible Electronics, 2022. DOI: 10.1038/s41528-022-00207-2 (About DOIs)

Rupendra Brahambhatt is an experienced journalist and filmmaker. He covers science and culture news and for the past five years has been actively collaborating with some of the most innovative news outlets, magazines and media brands operating in different parts of the world.