If the lightweight “Jaipur foot” was an innovative answer to human disability, two scientists native to the city have come up with an ingenious solution to enable robots to overcome their big handicap — lack of tactile sensation.

Prof Ravi Saraf and Dr Vivek Maheshwari of the department of chemical engineering, University of Nebraska, Lincoln, US, have developed a nanotech method of giving robots a human touch. The work of both scientists, who trained at Indian Institutes of Technology, is being reported in the latest issue of Science.

Touch, a feeling we take for granted, is the result of a highly developed nervous system, with its extensive distribution of sensors on our largest organ, the skin. Replicating this in an artificial system has proved extremely difficult.

Saraf and Maheshwari have created a thin film made of layers containing nanoparticles of gold and semiconducting material. Electrodes are linked to either side of the film.

When the film comes into contact with something, the pressure changes the passage of current and causes light to be emitted from the particles, producing an image of the object or surface touched. A specialised camera captures this light.

To demonstrate how this works, the authors pressed a five-rupee coin against the film, producing an image detailed enough to show the delicate markings of the Ashoka pillar emblem. The film can be literally coated onto a robot’s fingers, almost like spreading a thin skin.

Saraf told The Sunday Express that “touch would be an important sensory capability that will tremendously enhance the functionality of a robot — it will quickly be able to tell if an object is smooth or has sharp edges, a property that optical systems will take longer to achieve, and with more computing power.”

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