Electronic Design

New Technologies Make Roads Safer... One Smart Car At A Time

Developments in sensors converge to make sure you get to where you want to go and back again in one piece.

Think about cars from the past. Actuators drove almost every mechanical and hydraulic system. Nowadays, there's an alphabet soup of electronic components and systems. Electronic sensors augment or have even replaced the various mechanical systems. Some high-end cars feature as many as 70 electronic-control units (ECUs). The average car has up to 35 sensors, while a high-end model has up to 60. The typical car also carries about a half-dozen airbags. What it all means is that today's cars are much more sophisticated, safer, and easier to drive. They're also much smarter than their predecessors, and they continue to acquire greater intelligence.

On the safety side, federally mandated standards will drive the inclusion of these features and others, like tire-pressure monitoring, in the next few years. According to market research firm IC Insights, the worldwide automotive IC electronics market will grow from nearly $13 billion today to nearly $20 billion by 2009. Market research data from iSuppli, Philips, and Strategy Analytics show growth in airbag, driver warning, security, and body and chassis electronics (Fig. 1).

More airbags that also are smarter are being deployed in vehicles. Hightech side curtain bags that provide head and neck protection for front-and rear-seat passengers are common in many cars. Front-impact airbags now include sensors that identify children and very small adults: The airbag will deploy with less force to minimize injuries to those occupants.

Many examples of "smart" cars are already out there. The Toyota 2006 Lexus LS460's Intelligent Parking Assist system, which processes images from rear and front cameras, uses the results to control electronic power steering and a "drive by wire" electronic throttle. The system parks the car with the touch of a button and with just a little braking on the driver's part.

Also, the LS460's Vehicle Dynamic Integrated Management system mines data from a variety of sensors to anticipate skidding. It uses this data, in addition to any inputs from the driver, to help the driver recover control of the car. It regains control by activating electronically controlled brakes, electronic power steering, anti-lock brakes, vehicle stability control, braking-assist, electronic brake-force distribution, and engine-torque features.

If that's not enough, the climate control system adjusts itself based on the ambient temperature, as well as on the body heat emanating from the car's occupants. With increasing car intelligence, though, consumers may begin to ask how much intelligence is necessary. Even the cars of the future should maintain some kind of driver control.

Radar And Cameras Emphasize Driving
After years of work to reduce deaths and injuries from car accidents through the use of seatbelts and airbags, automakers and their suppliers are shifting to technologies that prevent accidents. For instance, clusters of LEDs on tail lamps and rear-window brake lights, as well as LED headlights, provide brighter illumination levels and last longer than regular light bulbs.

On cars like the Mercedes-Benz S-class, 24/77-GHz radar-guided systems play a big role in improving safety. Brake Assist, Parking Assist, Pre-Safe, Distronic Plus, and Adaptive Brake features use seven radar sensors (five in the front bumper and two in the back bumper) to greatly enhance safety levels (Fig. 2).

With these features, the car can sense an impending crash, enabling the driver to take evasive action. The radar system allows for automatic brake application. Plus, it will close the sunroof and tighten the seatbelts if a potential collision is detected.

Speaking of radar, today's radar-based, adaptive cruise-control systems are flourishing. They can be found in many Mercedes-Benz and Toyota models. The Volkswagen Passat, as well BMW's Series-3 cars, also feature such radar.

To improve traffic safety, Nissan developed its Distance Control Assist System to help drivers control the distance between themselves and the vehicle in front of them. The system determines the following distance of the driver, as well as the relative speed of both cars, using a radar sensor in the front bumper (Fig. 3).

If the driver releases the accelerator pedal or isn't pressing the accelerator pedal, the system automatically applies the brakes. If the system determines that braking is required, an indicator appears on the instrument panel and a buzzer sounds. The accelerator pedal then automatically moves upward to help the driver switch to the brakes.

Cameras, another key feature, give drivers a better view as they back into tight parking spots and perform other visibility-limited maneuvers. Studies show that many children have been killed as a result of drivers not being able to see them as they back into parking spots.

Sophisticated all-wheel-drive was once the bastion of only high-end cars. Now, it's a standard feature on many vehicles. These systems deliver optimum power in bad driving conditions by instantly delivering power to the axle that needs it the most.

The concern for safety extends to the headlights. Chrysler's 300C features the SmartBeam system, developed by Gentex Corp. It turns the car's front bright lights on and off automatically according to road conditions (Fig. 4). A forward-facing CMOS image sensor is built into the rear-view mirror. It keeps the bright lights switched on until it detects the headlights or taillights of other cars on the road, and then it switches to low beams. To avoid distracting approaching drivers, the system fades the high beams on and off.

The Mercedes-Benz S-class cars have two infrared (IR) headlamps that illuminate the road. They extend the driver's range of vision to more than 150 m when the car's low beams are on, making pedestrians, parked cars, and other obstacles visible much sooner. It also reduces the risk of collisions while driving in the dark.

Safer tires are on the way, too. Some tires can even run flat-free for long distances. Ever since Congress enacted the Transportation Recall Enhancement Accountability And Documentation (TREAD) Act in 2000, there's a been a flurry of activity to comply with the safer-tire mandates.

Researchers at Purdue University developed a system that uses sensors and mathematical models to detect defects in newly manufactured tires. The researchers say it's better than conventional test methods and promises to meet stringent federal tire-durability requirements.

Automotive electronics now let drivers customize their own dashboard displays. At April's Embedded Systems Conference in San Jose, Toshiba demonstrated one of these dashboards using its TX9461 real-time display controller system-on-a-chip (SoC) controller. This IC contains a CPU, a graphics accelerator, and a video frame grabber. It can display a "virtual" dashboard, replicating an analog speedometer, tachometer, and other instruments (Fig. 5).

Vehicles equipped with rear-view image sensors can display the view behind the car on the virtual dashboard, instead of compressing the image onto an auxiliary screen. Drivers also can use the dashboard to view navigation systems, speed, fuel levels, and other information minimized or maximized according to their preference.

A Safer Driving Envrionment
Government researchers are considering the safety benefits of a wireless infrastructure that could vastly improve the driving environment and make roads safer. So far, wireless technology has been limited to cellular phones in automobiles. But this may change as these researchers look further into using Wi-Fi communications for a safety infrastructure of roadside stations.

The Department of Transportation's (DOT) Vehicle Infrastructure Integration (VII) Initiative seeks to use wireless links for collision avoidance. Basestations would inform and alert other stations and drivers about a vehicle approaching an intersection or a blind corner. The system also would provide data on traffic speed and density, enabling roadside signs to inform drivers about backups before they enter a highway.

The DOT has a cooperative arrangement for the initiative with the National Highway Transportation Safety Administration, the Intelligent Transportation Systems Joint Program Office of the Federal Highway Administration, and the Federal Motor Carrier Safety Administration. Late last year, the University of Michigan's Transportation Research Institute landed a $25 million contract from the DOT to join this initiative.

UMTRI is partnering with Visteon Corp., AssistWare Technology Inc., Honda R&D Americas Inc., the Eaton Corp., the Battelle Research Institute, and the Michigan Department of Transportation to work on this program. The partners will develop integrated, advanced technologies that will warn drivers of various scenarios: when they're about to leave the roadway, when they're in danger of colliding-with another vehicle while attempting a lane change, and when they're at risk of colliding with a vehicle in front of them.

Big Brother Watching
Interactive communications envisioned in the VII Initiative brings with it vast implications for privacy. It may reach the point where drivers might feel "Big Brother" is watching over their shoulders and tracking their every move.

Take General Motors' latest OnStar system. Not only can it monitor dozens of functions like oil pressure, water pressure, and gasoline levels, it also can detect when a car is being driven too aggressively. It achieves this by comparing the car's performance data to its norm, which is stored in OnStar's databases. If the OnStar monitoring center in Troy, Mich., deems that the car's on-road activities are too extreme, it calls the driver to make sure everything is okay.

Given the present capabilities of a system like OnStar, it's not unrealistic to expect such technology to, say, slow a car down or even shut down its engine. While there are some safety and even law enforcement benefits, nobody knows how many drivers would want it on their own cars.

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