Electronic Design

From Mpg To DARPA Challenge: Electronics Winning The Race

Gas at my favorite filling station fell to $2.59 today—quite a bargain after last month's $3.25+ prices. The relativity of fuel pricing has never been more apparent. A recent AP poll of consumers in eight countries shows what they felt was a fair price for a gallon of gas.

Not long ago, most Americans would have thought $2 a gallon a steep price to pay. But in the wake of the Katrina-related run-up, we now say $2 a gallon is a fair deal. Meanwhile, in England where a gallon fetches $6.40, consumers think $5 sounds dandy. The French, Italians, Germans, and South Koreans consider $4 a gallon square-deal pricing, while Australians and Canadians would like to see gas at $3.

With our gas-guzzling SUV culture on rocky ground, the EPA's mpg rating sticker is suddenly center focus in car ads and showrooms. For 2006 vehicles, the EPA's ratings show the Toyota Prius edged out of the top spot by the Honda Insight. Both cars were rated at 60 mpg in city driving. But the Prius' highway consumption, where the gasoline engine kicks in, drops to 51 mpg, while the Insight (which integrates three-cylinder gas and ultra-thin electric motors) kicks up to 66 mpg on the freeway. Still, the Prius is rated as a mid-size car, while the Insight is a twoseater. Roger Allan, who test-drove the Prius to write this issue's cover story on the car's engineering, averaged 47.5 mpg.

Europeans long ago bit the bullet and levied steeper gas taxes (two-thirds of the price of gas there) to encourage public transport and higher-efficiency cars. With gas at $6.70 a gallon in Germany, it is no surprise that Volkswagen has perfected the high-efficiency diesel engine that powers four out of the top-10 EPA-rated cars. The Beetle and Golf take top spots in the compact and sub-compact categories, each with an estimated 44 mpg on the highway and 37 mpg in the city.

DRIVERS NOT REQUIRED Stanford University's robotic Volkswagen Touareg, a.k.a. Stanley, won the 2005 DARPA Grand Challenge in the Mojave desert last month, netting the $2 million prize. Stanley traversed the 130-mile off-road course in six hours and 53 minutes, one of five of the 23 entrants to finish. Stanley autonomously negotiated such challenges as "Beer Bottle Pass," a winding mountain pass with hairpin turns and a steep drop on one side of the road.

Stanley was built from a stock, diesel-powered Touareg R5 modified with full-body skid plates and reinforced front bumper. It was actuated by a drive-by-wire system developed by Volkswagen Electronics Research Laboratory (ERL). Six Pentium M computers handled the processing. These computers incorporate measurements from GPS, inertial sensors, wheel speed, lasers, a camera, and radar systems.

DARPA funded the contest with the goal of advancing autonomous vehicles for use in dangerous wartime convoy and reconnaissance situations. Volkswagen and challenger-car sponsors like Texas Instruments and Analog Devices looked at the race as a means to advance automotive electronics. The research will help further active-safety and driver-assist technologies, such as intelligent cruise control, collision-avoidance, intelligent lane-change, and other leading-edge technologies.

The race proves that current hardware tools are capable of autonomous vehicle control, but the biggest challenge for the teams was in the programming. The Stanford team had to log long hours tweaking, while Stanley trained in the desert, propagating its custom-written machinelearning algorithms.

Eliminating software bugs will pose the biggest challenge as cars move from hybrids to more fully electronic and autonomous machines. Last month's voluntary recall by Toyota of 2004 and 2005 Priuses was to correct a software problem that caused the gasoline portion of the engine to occasionally cut off, though the electronic portion of the engine was still operating.

The increasing complexity of code provides a good reason for the pursuit of open-systems standardization initiatives, like Autosar and JASPAR, for more modular software in the automotive marketplace. The challenge of "runaway software code" goes beyond the automotive market to all embedded applications. Johan Wall, the CEO of Enea, a long-time embedded operating system vendor, stopped by our offices recently. He discussed the need for more reusable software across multiple platforms and the company's decision to join and support the Device Software Optimization framework. According to Wall, time-to-market and cost pressures, coupled with a potential worldwide developer shortage, will force the issue on software modularity.

Hats off to the Stanford University team and the Volkswagen ERL for their historic work on the hardware integration and software programming fronts. Congrats also to the two teams from Carnegie Mellon that finished just minutes behind the Stanford team and to the fourth-place Gray Team from Metairie, La., which included team members who had lost their homes (and valuable practice time) due to Hurricane Katrina.

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