Smart glove made from a sensory film

Researchers from Saarland University have created an ultrathin flexible film, integrated within a glove, that can act as a sensor for innovative technologies. By establishing a direct connection between the virtual and real working worlds, man and machine can, quite literally, work hand in hand.

Consider a situation where an assembly operator discovers that they have used the wrong component and so they now have to take apart everything that they had previously assembled. This takes time and results in production delays. This could be avoided if the computer had been able to flag up the error while the operator was taking the component from the storage bin — but the computer was completely unaware of the mistake. Now, thanks to the smart glove developed by Professor Stefan Seelecke and his team, this information can be made available to the computer system.

The researchers took an ultralightweight, highly flexible film made from an elastic polymer and turned it into an adaptable sensory organ for a variety of technical applications. By lining a glove with the polymer film, they can create a man–machine interface without the need for heavy sensors or cameras — it’s all done with the ultrathin film, which is not felt by the wearer and does not restrict them when carrying out their work.

“The film we use is known as a dielectric elastomer, and the glove essentially functions as a flexible sensor,” said Professor Seelecke, who heads research teams at the Intelligent Material Systems Lab at Saarland University and at ZeMA (Center for Mechatronics and Automation Technology) in Saarbrücken.

An electrically conducting material is printed onto both sides of the silicone film. When voltage is applied to the film, the resulting electrostatic attractive forces cause the film to compress, extending the film laterally and thus increasing its surface area, which in turn alters the electrical capacitance of the film. This property effectively transforms the film into a sensor.

“We can assign a precise electrical capacitance value to any particular position of the film,” said Steffen Hau, an engineer working in Prof Seelecke’s team.

The team members know at any moment just how a finger is stretching, pulling or compressing the film. Using algorithms, the team is able to compute these motion sequences in a control unit and then process the results with a computer.

The thin silicone film is not just a sensor — it can also be made to pulse or vibrate on demand or to take up any required shape. The researchers can precisely control the film and can continuously vary the frequency of its motion as required, from high-frequency vibrations down to a slow pulsing or flexing motion.

For the next stage of the development process, the researchers want to enable the glove to communicate directly with the wearer, by means of pulses or vibrations that would be sensed by the wearer’s fingers. Hau noted, “The computer could then send, for instance, a pulsed signal to the operator’s fingertips to tell them ‘You’ve taken the wrong component’, or a vibrating signal to confirm ‘That is the right component’.”

Image caption: Doctoral student Sebastian Gratz-Kelly from Professor Stefan Seelecke’s research group demonstrates the prototype glove. Image credit: Oliver Dietze.

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