New soft actuator endows robots with a bit of give and take

The Max Planks Institute's soft actuator is designed to allow robots to work alongside humans more safely(Credit: Alejandro Posada)

The first law of robotics, according to Isaac Asimov, states that a robot must not injure a human being, or through inaction, allow a human to come to harm. But until robots are smart enough to understand such a law, we have to rely on other techniques. With this in mind, a team of researchers at the Max Planck Institute for Intelligent Systems has developed a new soft actuator that makes it safer for humans and robots to work alongside one another.

Current industrial robots are often bolted to the factory floor and surrounded by cages to prevent unwary workers accidentally getting in the way of a robot relentlessly going about its task. Although generally safe, this limits the ability of automated machinery to work in tandem with humans on a production line.

While there are robots out there with soft actuators that offer some give when coming into contact with an unexpected object, such as a person, they generally involve complex pneumatic hoses connected to pumps and compressors that limit the robot's movement.

The system developed at the Max Planck Institute doesn't require any external pneumatic hoses, thanks to a dielectric elastomer actuator, or DEA. This is a membrane that looks like a latex balloon, with flexible electrodes attached to either side. How far the membrane stretches is regulated by an electric current, because the electrodes attract each other and squeeze the membrane when voltage is applied.

If knocked or bumped, the membrane is flexible and will deform instead of the robot pushing through the contact and potentially injuring the person who got in its way. The researchers say the place of deformation can also be shifted controllably through the use of multiple membranes.

"We have developed an actuator that makes large changes in form possible without an external supply of compressed air," said Metin Sitti, Director at the Max Planck Institute for Intelligent Systems

At the moment, the researchers are working to nail down a hyperelastic polymer with the right deformation properties. Beyond that, they're hoping to integrate the actuator into a robot, allowing it to move its legs, for example, but also deform to "give way" to a human.

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