Researchers Develop Soft Robotic Insect with Artificial Muscles

Researchers at EPFL’s School of Engineering have developed a type of soft robotic insect that has artificial muscles, and it can be propelled at 3 cm per second. 

The recent advancements in both artificial intelligence (AI) and robotics are bringing us closer to a world that could not have been predicted. It is a world that contains such things as swarms of robotic insects. 

There were two different versions of the soft robotic insect, called DEAnsect, developed by the team. The first was tethered by using ultra-thin wires, and it is extremely robust. It is capable of being folded, and it can even continue to move after being hit by a fly swatter or smashed by a shoe. 

The second model that was developed by the researchers is an untethered model. It is fully wireless and autonomous, and it weighs less than 1 gram even while carrying a battery and all of its electronic components on its back. For the brain of the intelligent robotic insect, there is a microcontroller, and the eyes are photodiodes. This allows it to identify black and white patterns, and the DEAnsect is capable of following any line that is drawn on the ground.

The DEAnsect was a result of work done by a team at EPFL’s Soft Transducers Laboratory (LMTS). They worked with the Integrated Actuators Laboratory (LAI) and colleagues from the
University of Cergy-Pontoise, France. The research was recently published in Science Robotics.

The DEAnsect has dielectric elastomer actuators, or DEAs. They are a type of artificial muscle that is as thin as human hair, and it propels the insect forward through the use of vibrations. The DEAs are what make the soft robotic insect so light and capable of moving quickly. The DEAs also help the soft robotic insect maneuver different environments, including undulating surfaces.

The artificial muscles contain an elastomer membrane that is placed between two soft electrodes. When a voltage is applied, the electrodes are attached to one another, and the membrane is compressed. The membrane then returns to its initial shape once the voltage is turned back off. 

Each of the three legs of the soft robotic insect has those muscles fitted to them. The movement is generated by turning the voltage on and off, but it has to be done very quickly. The actual rate is 400 times per second to propel the soft robotic insect.

The research team relied on nanofabrication techniques in order to enable the artificial muscles to work at lower voltages. Specifically, they reduced the thickness of the elastomer membrane. They also developed soft, highly conductive electrodes that are only a few molecules thick. Because of this design, the researchers were able to greatly reduce the size of the power source.

Herbert Shea is the director of LMTS.

“DEAs generally operate at several kilovolts, which require a large power supply unit,” Shea explains. “Our design enabled the robot, which itself weighs just 0.2 gram, to carry everything it needs on its back. This technique opens up new possibilities for the broad use of DEAs in robotics, for swarms of intelligent robotic insects, for inspection or remote repairs, or even for gaining a deeper understanding of insect colonies by sending a robot to live amongst them.”

“We're currently working on an untethered and entirely soft version with Stanford University,” says Shea. “In the longer term, we plan to fit new sensors and emitters to the insects so they can communicate directly with one another.”