A method for making remote-controlled cyborg cockroaches has been developed by an international team led by scientists at the RIKEN Cluster for Pioneering Research (CPR). The system includes a tiny wireless control module that is powered by a rechargeable battery coupled to a solar cell. Despite the mechanical gadgets, the insects may move freely thanks to flexible materials and ultrathin electronics. These developments, which were published on September 5 in the academic journal npj Flexible Electronics, will contribute to the widespread use of artificial insects.
In order to help check dangerous regions or monitor the environment, scientists have been attempting to create cyborg insects, which are partially insects and partially machines. The ability to control cyborg cockroaches remotely for extended periods of time is necessary for their use to be viable, though. This necessitates cordless, rechargeable, battery-powered control of their leg segments. Nobody wants a team of robotic cockroaches running about who are suddenly out of control, so keeping the battery fully charged is essential. Although docking stations for charging the battery could be constructed, the requirement to return and recharge might interfere with missions that must be completed on schedule. In order to ensure that the battery is constantly charged, the best solution is to incorporate an on-board solar cell.
All of this is easier said than done. The research team had to make a special backpack, ultrathin organic solar cell modules, and an adhesion system that keeps the machinery attached to cyborg cockroaches for long periods of time but still lets the cockroach move naturally in order to successfully put these devices on a cockroach with a small surface area.
The team conducted research using 6 cm long Madagascar cockroaches under the direction of Kenjiro Fukuda, RIKEN CPR. They used a specially created backpack that was based on the body of a model cockroach to attach the wireless leg-control module and lithium polymer battery to the top of the bug on the thorax. The hard electronic equipment was able to be securely attached to the thorax for more than a month thanks to the elastic polymer backpack, which was 3D printed and flawlessly contoured to the curved surface of the cyborg cockroaches.
The dorsal side of the abdomen was mounted with a 0.004 mm thick organic solar cell module. Fukuda claims that the power output of the body-mounted ultrathin organic solar cell module, which is 17.2 mW, is more than 50 times greater than the power output of the most advanced energy harvesting devices currently being used on living insects.
Movement freedom was made possible by the organic solar cell’s ultrathin and flexibility, as well as how it was attached to the insect. The researchers discovered that the abdomen changes shape and parts of the exoskeleton overlap when they closely examined the motions of cockroaches in their natural environment. They interspersed adhesive and non-adhesive sections on the films to accommodate this, allowing the films to bend while maintaining their bond. The cockroaches took twice as long to run the same distance when thicker solar cell films were tested or when the films were uniformly attached. They also had trouble getting back up after falling.
The new cyborg cockroaches were evaluated after these parts, together with cables that stimulate the leg segments, were incorporated into the insects. After simulating sunlight for 30 minutes to charge the battery, the remote control was used to make the animals turn to the left and right.
According to Fukuda, a hybrid electronic system with hard and flexible elements in the thorax and ultrasoft devices in the abdomen looks to be an appropriate design for cyborg cockroaches. “Considering the deformation of the thorax and abdomen during fundamental locomotion,” he adds. Also, other insects, like beetles and maybe even flying insects like cicadas in the future, also have deformed abdomens, so our method can be used on them as well.
