Since I've been working on a market report on printed and organic sensors, my conversations have tended to include topics such as electronic noses and artificial/smart skin. I think that my son-in-law (a science fiction fanatic) is half convinced that I'm building a robot in my basement. Understand that I would love a robot to help around the house and perhaps in the yard. Unfortunately, there is no robot under construction in my basement.....and there probably won't be one for some time.

To date, robotics technology in the private sector has mostly been confined to industrial production, in the form of large and small devices used to manufacture everything from microchips to cars. According to the Robotics Industries Association, approximately 180,000 have been installed in the United States since their inception in the 1960s. Used mainly in the automotive industry for welding and material handling, converts have been very positive about their advantages and growth in this sector has averaged in the 20% range. However, there has been little success in moving robotics beyond industrial applications into the domestic military or medical sector. The robot that would help clean the house, protect workers in hazardous terrain, perform surgery, care for patients, and entertain children is still the stuff of science fiction. Several times in the last 25 years, experts have declared that this was the year of the robot. It has never materialized.

There is definitely hope though and considerable progress underway towards solving some of the challenges in constructing such a robot. Specifically, I am talking about research on the development of smart skin. Before there could be any consideration of moving robots out of their present structured environment, they would have to be much more sensitive to their surroundings.

The task is not without its challenges. Artificial skin needs to be flexible, stretchable and sensitive to pressure, temperature, humidity etc. It must be able to be manufactured in large quantities to cover an entire robot. The University of Tokyo has been doing research for several years and has succeeded in overcoming many of those challenges.

The prototype that they have been working on consists of a checkerboard of pressure and temperature sensor arrays fabricated from organic transistor circuits laminated onto a plastic film. While the arrays are less sensitive than human skin, they are already an improvement over previous efforts able to register temperature in the range of 30-80º C and pressures up to the weight of approximately 30 pennies stacked.

Moreover, the film is flexible enough to be rolled or bent around a spindly robot finger. To provide the flexibility to cover joints, the researchers processed the film with its integrated circuits into a mesh or net structure (resembling a fishnet stocking) whose struts twist when tension is applied. The resulting net is extendable by 25%about twice the deformation of the skin on a bent elbow. The group concentrated on flexibility first, so the areas of sensitivity to light, humidity and strain had to wait. However, researchers feel it is all doable&but probably won't be ready for commercialization for another four to five year.

Another concept has been developed by Tekscan. Here, the skin is constructed by laminating two 25 ¼m-thick polyester sheets with adhesive in the non-sensing area. These sheets carry parallel, thermoplastic, Ag-filled polymer conductive traces covered by a thermoplastic semiconductive ink. This ink, unique to Tekscan sensors, provides the electrical resistance change at each of the intersecting points. The two sheets were oriented together so that their traces formed a grid, with the semiconductive layers facing each other, so that each cross section of the grid formed a contact piezoresistive force sensor.

The resulting smart skin was thin (circa 100¼m) and flexible. The resolution of the array is limited only by the resolution of the printing technology. For screen-printing on large area substrates (thousands of centimeters squared) were registration accuracy becomes more demanding, the highest practical sensor resolution is around 250 sensels/cm2. While Tekscan has not commercialized its concept into smart skin for robotics applications, it has done so for smart textiles. They also feel it is doable for robotics, but were unwilling to provide a timeframe.

So I can still dream of having a robot in my basement to help with my chores. I doubt that I could build one, but the technology to do so is over the horizon.