Science Details Development of Sensitive Sensors for Robotic Hands

A new type of sensor offers the first step toward giving robotic hands the delicacy of the human touch. The device, described in the 9 June issue of Science, has tactile sensitivity comparable to that of human fingers and could be useful for the next generation of minimally invasive surgeries.

Many operating rooms already have robots that that play supporting roles during surgery, especially in minimally invasive surgeries, where the surgeons make tiny incisions and use tiny tools so they can target very specific areas in the body. Patients heal much faster from such surgeries. Tiny robots that could do more of the work by themselves might perform the next generation of such surgeries, but they'll have to be able to "feel" the way human hands do.

The “electroluminescent” thin film, designed by Vivek Maheshwari and Ravi Saraf of the University of Nebraska at Lincoln, glows in response to an applied force, and the light is captured by a specialized camera. To illustrate how this works, the authors pressed a U.S. penny against the sensing device, producing an image detailed enough to show the wrinkles of President Lincoln's clothing and the letters “TY” in “LIBERTY.”

The thin film is composed of alternating gold and semiconducting cadmium-sulfur nanoparticle layers separated by dielectric films. At biases exceeding 8 volts, applied stress enhances electron tunneling between the layers, inducing an electroluminescent response that is linearly proportional to the pressure. Scaling up tactile sensors beyond millimeter dimensions has been a major hurdle until now.

More research will be required before such sensors could be used in the operating room. But the basic idea is that a robot's "hands" might be coated with a film like this, and the camera could be connected to the computer controlling the robot. The robot could then sense different surfaces with the sort of sensitivity that human fingers have.

13 June 2006