A prototype of the microelectromechanical system (MEMS) device that University of California-Irvine engineers designed for a next-generation electronic stability control system contains a built-in gyroscope. *Photo courtesy of UC Irvine.
Scratch and Fix
Having a car door get keyed is enough to make you feel sick. University of Illinois Urbana-Champaign researchers have developed a coatings additive to let the healing begin. The scientists developed microcapsules, or “micro-balloons,” made up of tin catalysts and a precursor to a silicon-based sealant, which are mixed into coating at 10% of the total volume. When coating is scratched, the capsules—roughly 100 micron in diameter—crack open, releasing the catalyst and the jelly-like sealant. The reaction “heals” the damaged area within minutes or hours, depending on the outside conditions. The researchers tested the material solution by using a razor blade to tear through a 100-micron thick self-healing polymer coating a steel substrate and did the same to a conventional coating protecting an identical steel substrate. After immersion for 24 hours in a salt solution, the control samples had rusted along the scratches, while the self-repairing samples did not—even after 120 hours. Paul Braun, a materials science and engineering professor who developed the technology, projects the first automotive applications will be interior coatings, underbody components, and even inside components such as fuel lines (in this case to prevent corrosion from the inside out).
Head-up displays (HUDs) are used in some higher-end cars like ZR1 Corvettes. These HUDs use liquid crystal displays or light emitting diodes to reflect data onto the windshield, but University of California School of Engineering researchers believe they’ve found a cheaper, if not smaller, solution that’s the equivalent of an electronic sticky note. It’s a flexible, colorless disk about 5 in. in diameter constructed from more than 20,000 transistors made from nanotubes that were first “grown” from quartz substrates and transferred to glass substrates with pre-pattered electrodes. The technique, also developed by USC, is to print or embed the electronics into the lattice itself. The clear thin film can then be affixed to glass, plastics and LEDs to illuminate and continuously update data or graphics. The nanotube transistors are fairly simple to fabricate and integrate, say their USC creators, who also envision integrating the film into fabric that could change colors or patterns in clothing. (No word on any upholstery applications).
Electronic Stability Control (ESC) has become a universal acronym since 2007, when the Society of Automotive Engineers asked automakers to use the generic term, instead of relying on branded monikers like Stabillitrak or AdvanceTrac. The next-generation of ESC may be predicated upon another abbreviation: MEMS, as in microelectromechanical systems, or tiny machines typically measuring between 1 and 100 mm. The University of California-Irvine hopes its 1.7 mm.-wide sensor with a built-in gyroscope will gain traction in that burgeoning MEMs market. When it senses the vehicle start to lose its footing, the gyroscope sensor alerts the safety system, which applies the brakes for the slipping wheels as needed. Andrei Shkel, a UCI mechanical and aerospace engineering professor, says the MEMs devices will prove less expensive than some of the quartz-based sensors found in most current ESC systems. Systron Donner Automotive (www.systronauto.com; Concord, CA) provided a portion of the research project’s funding.
The clogged streets of Boston have proven an ideal test bed for a Massachusetts Institute of Technology project aimed at shortening commuting time. Dubbed “CarTel,” the project has equipped 50 cars—including 40 taxis—with a cell phone-sized sensor that monitors vehicle speed, location, and time of day, and relays up to 600 data points per second back to a sever via available WiFi networks. MIT software compares the data to both the daily norm and to incoming information from other vehicles armed with same CarTel sensors. The system responds with real-time traffic guidance, alerting drivers to traffic jams as—or even before—they happen, and provides suggested alternative directions to users’ cell phones or other mobile devices. The more cars using the system, the more focused the picture of traffic conditions that emerges. “Everybody's data is contributing to collective views of what congestion looks like," says Samuel Madden of MIT's department of electrical engineering. One of the researchers says the network has shortened his commute by 25%.
Where are those smart highways of the future, like the ones that take over a car when it gets on a freeway and relinquishes it back to the driver when the car comes off the exit ramp? The on-ramp to this future may start in San Leandro, CA, where University of California-Berkeley engineers recently guided a 60-ft city bus equipped with sensors and a small processor via magnets embedded along a one-mile stretch of pavement. Following the line of magnets, the bus pulled into regular stops within one cm of the curb. Sensors mounted under the bus measured the magnetic fields created from the roadway magnets, embedded under the pavement and spaced about one meter apart along the center of the lane. The on-board processor translated and directed the bus's lateral and longitudinal position, and managed the steering with an actuator, while a driver operated the gas and brakes. “A number of states and the Congress have been discussing the feasibility of a dedicated truck lane,” says Wei-Bin Zhang, program leader for the California Partners for Advanced Transit (PATH) at UC Berkeley. “The automated highways will become a logical and natural choice for travelers when bus and truck automation is widely deployed.” Zhang says a guidance system could be deployed in U.S. cities within the next five years.