New Technique for Making Safer Robots

Soft ActuatorSoft actuators are emerging in robotics because they are lightweight, affordable, and could potentially be safer around humans than traditional rigid robots. However, elastic actuators (stretchy membranes that get filled with air) usually must be connected to pumps and compressors in order to work. Researchers at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany have developed an alternative. Their soft actuator uses a new method that saves space and eliminates the restriction of a tether.

We have developed an actuator that makes large changes in form possible without an external supply of compressed air.

Metin Sitti, Director at the Max Planck Institute for Intelligent Systems.

The new soft-actuator consists of a dielectric elastomer actuator (DEA): a membrane made of a balloon-like material with flexible electrodes attached to each side. Instead of using compressed air, the stretching of the membrane is regulated by an electric field between the electrodes, as the electrodes attract each other and squeeze the membrane when voltage is applied.

The team tested different potential materials for the membrane to find a polymer that would be strong and flexible enough to quickly deform. The material they used has two stable states, so it can handle air moving between a highly inflated chamber and a less inflated one without completely deflating. To move the air, the researchers apply an electric current to the membrane of the smaller chamber, which reacts by stretching and sucking air out of the other bubble. The membrane contracts to its smaller (but still stretched) size when the power is switched off. They are now working on integrating the soft actuator into robots to enable safe interactions between robots and humans.

Source: Max Planck Institute | Image by Alejandro Posada

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