Robots have mastered picking and placing, welding, and similar tasks that can be precalibrated, but they cannot perform tasks that requite a sense of touch, such as "feeling" when a bolt's threads mesh before screwing it in. Even the most accurate robots today will strip the threads on bolts and otherwise damage items that require a sensitive tactile sense. Electrical engineers at the University of Illinois (Urbana-Champaign) say they are on the way to solving this problem. The team has created a prototype robot "skin" from a flexible polymer with multiple sensors that simultaneously assess shape, force, hardness, motion, temperature and thermal conductivity. Robots with a sense of touch are rare, but even those with touch sensors usually just have a single strain gauge, making it impossible for them to determine the hardness of an object or even how hard they are squeezing it. Applying the same pressure to different objects may cause the robot to drop one that is very hard and slippery or break another that is soft and fragile. The challenge is to enable the robot to sense the material from which the object is made so that it can adjust its grip accordingly.
Monday, May 30, 2005
NeuroSky Inc. wants to get into your head. By fusing brain wave recognition algorithms with a sensor chip and dry electrode, NeuroSky hopes to simplify cell phone-based applications that today require error-prone human input, as well as revolutionize applications from gaming to medical diagnostics and therapy. Conventional EEGs require the use of greasy paste to reduce the impedance between an electrode and a person's skin, but NeuroSky's dry electrode just needs to touch the forehead via a pod that can be attached to virtually any headset. Five companies, including a Bluetooth headset provider, game console maker and trucking company, are said to have signed up to market end-user products containing NeuroSky's chips. Its biggest customer thus far is Ziyitong Technology Co. Ltd. (China Mobile), which has more than 100 million cell phone subscribers, 13 million of whom have high-speed 3G service.
Monday, May 23, 2005
With SRAM, DRAM and flash high-stepping down the road map for both standalone and embedded designs, any competing memory chip technology faces an uphill battle. Nevertheless, other types of memory � in various stages of development � are rumbling offstage. Ferroelectric random-access memory, for example, has entered mass production at Ramtron International Corp. and is close to commercialization elsewhere. Beyond FRAM comes a bewildering array of alternatives, some still in basic research and all aiming to shrink design rules toward the angstrom scale (an angstrom is one-tenth of a nanometer). Among the contenders are magnetic tunnel-junction RAM (MRAM), phase-change RAM (PRAM), nanowire and nanotube designs, and molecular memories. For any of these, however, gaining traction will probably mean following in the footsteps of Ramtron and finding a niche in which to flourish while sustaining the long-term research required to someday catch up to DRAM and flash.
Posted by R. Colin Johnson at 7:00 AM
Metamaterials that are able to reverse basic optical properties of conventional lenses and microwave antennas are being explored as a superior optical medium. Normal materials refract electromagnetic radiation by bending it away from the angle of incidence, which requires that lenses be convex in order to focus. Left-handed metamaterials, on the other hand, bend light toward the angle of incidence, thereby enabling a planar lens to focus radiation to a point. "Using left-handed metamaterials, we can build novel, smaller, lighter-weight lenses, sensors and antenna systems than those that are available today," said Srinivas Sridhar, a professor at Northeastern University. "Besides cheaper and better, our form factor is also more flexible, because metamaterials can conform to odd shapes since they are composed mostly of air. In our experiment, we used a periodic array of aluminum-oxide rods in air laid out in a lattice like a photonic crystal." Sridhar performed the work with research associates Patanjali Parimi and Wentao Luj as well as doctoral candidate Plarenta Vodo. The "meta" in metamaterials means they substitute macroscopic objects-rods in this case-for atoms in a macrosized, crystalline-like lattice. The pitch of the lattice's grid sets the wavelength affected. Unlike normal lenses, that wavelength can be set to an arbitrarily small subwavelength, giving the lens a nearly infinite focusing and resolution capability.
Monday, May 16, 2005
Robots at Cornell University are making copies of themselves without human intervention. In principle, the machines will thus be able to repair and reproduce themselves in space and other remote environments. "Our self-replicating robots perform very simple tasks compared with intricacies in biological reproduction," said engineer Hod Lipson, a Cornell assistant professor. "But we think they demonstrate that mechanical self-reproduction is possible and not unique to biology." Self-replication is sometimes seen as the holy grail of robotics. The goal of the engineers' work is to draw upon biological principles to enable robots to repair themselves as well as assemble "helpers." Such a capability would be especially useful in space, on the ocean floor or inside a "hot" nuclear reactor after a spill.
Independent tests appear to support an inventor's claim that his skunk-works antenna design can shrink antenna size by up to 70 percent while maintaining equivalent sensitivity and increasing bandwidth. The four-part antenna cancels out the normal inductive loading in traditional antenna designs, thereby linearizing the energy radiation along its mast and enabling its diminutive size. "When we announced my smaller antenna design last year, I got lots of doubting Thomases worldwide. Now, with the help of the Naval Undersea Warfare Center and its antenna test range on Fishers Island, N.Y., we have independent test results to back up our claims," said inventor Rob Vincent, a research engineer in the University of Rhode Island's physics department. Vincent calls his invention a distributed-load monopole (DLM) antenna. The novel design uses a helix plus a load coil to shrink the size of a normal quarter-wave monopole. According to Vincent, his design can shrink the size of every antenna in use today, from the tiny gigahertz units inside cell phones to giant, kilohertz AM antennas. For instance, a 3-inch-long gigahertz antenna could be shrunk to an inch, and a 300-foot-tall AM band antenna could be reduced to 80 feet high. In the tests, various DLM antennas from Vincent's portfolio were tested from 7 to 27 MHz. The results indicated that equivalent performance was achieved with antennas 30 to 70 percent shorter than an ideal quarter-wave antenna. (See the results at www.uri.edu/news/vincent/report05/testreport.pdf).
Monday, May 09, 2005
Silicon nanowires could combine the best features of carbon nanotubes and amorphous silicon to overcome the liabilities of the circuit technologies being explored for large-area flexible substrates, research at Harvard University suggests. Potential applications for such substrates include disposable e-newspapers and wall-hanging displays. Two of the candidates, amorphous silicon and organic semiconductors, are inherently slower than silicon. And while carbon nanotube transistors promise higher electron mobility than is possible with silicon, the tubes have not yet been demonstrated in an integrated circuit. The payoff of the Harvard work, the researchers maintain, will be a material with the electron mobility of nanotubes but with the low-temperature processing of organic semiconductors. The team demonstrated a nanowire-based ring oscillator that operated at 12 MHz. While that is dismally slow by CMOS standards, it's still 20 times faster than today's integrated organic semiconductors. The researchers believe they can scale the approach to CMOS speeds in the future. "We are not exploiting nano to build ultrasmall nanoscale devices; we are exploiting it to bring high-performance devices to an application area where the only competing materials are . . . low-performance or low-mobility materials," said Harvard professor Charles Lieber, who designed the ring oscillator chip with Harvard EE Donhee Ham.
Monday, May 02, 2005
Growing carbon nanotubes on silicon chips could enable nanoscale transistors, but only if designers can specify exactly where the tiny devices grow. Now EEs at Cleveland's Case Western Reserve University have demonstrated how to grow nanotubes just precisely where you want them � self-aligned across a wafer and self-welded during growth. The Case Western EEs claim that their nanotube-enabled wafers merely need to be diced and the dice wire-bonded to a chip carrier. If that's indeed the case, the devices could be as reliable and cost-effective as current chips. "The nanotubes grow where you want them to grow � between two electrical posts," said Case Western EE and computer science professor Massood Tabib-Azar