Auto Electronics

On the road to autonomous safety

There is no question that safety is a vital element in new car design, and it will be a key growth driver in the automotive market for at least the next 10 years. For instance, the European Parliament has recently adopted an initiative designed to cut in half the number of road accident victims by 2010[1]. This is an aggressive goal, but it demonstrates the high level of concern.

For the past several years, the industry has been concentrating on vehicle systems designed to reduce the effects of an accident, such as antilock braking systems (ABS) and vehicle stability control, and those systems to mitigate the impact of an accident, including smart airbags and passenger restraint systems. As the world leader in automotive semiconductors, Freescale has been heavily involved in this effort, and is now working to fuse these systems with emerging technology designed to avoid collisions altogether.

Electronic stability control (ESC) has demonstrated that it can be the difference between an accident and a near accident. Study results from the Insurance Institute for Highway Safety show that ESC can reduce single-car accidents by as much as 41%[2], and we provide some of the technology that makes that happen. For instance, we've developed low-g sensor solutions that provide critical vehicle pitch and yaw data, on multiple axes, which can trigger an automatic ESC intervention, applying precise brake pressure to the appropriate wheels to regain vehicle stability.

Ultimately, safety systems will be smart, aware and automatic, each an essential part of the autonomous car, but even now there are simple autonomous systems in many cars — lights that turn on when it's dark and wipers that switch on when it starts to rain. There are also widely used systems with limited autonomy — drivers don't have to flip a switch to turn on ABS, but they do have to hit the brake pedal to activate it. However, when we start moving into the autonomous collision avoidance arena, the car must first be able to detect what's going on in the nearby environment outside the vehicle before any automatic reaction can be initiated.

Freescale is developing silicon, germanium and carbon (SiGE:C) BiCMOS circuit solutions for automotive radar applications. Combining radar with camera technology can provide awareness feedback for such applications as adaptive cruise control (ACC), stop-and-go cruise control, blind-spot detection, lane departure warning and active pre-crash systems to mitigate the impact of a collision. For instance, 77 GHz radar with a 200-meter range provides accurate feedback for ACC to react to traffic conditions and automatically slow the car. Combine 77 GHz radar and 360° of shorter-range 24 GHz radar, plus some sophisticated algorithms, and the same kind of system can be adapted to very low speeds in high vehicle concentrations — city-going stop-and-go cruise control.

AUTONOMOUS SAFETY

By using radar and visual sensor equipment to quickly locate dangerous circumstances, the autonomous car will be able to activate systems to take corrective actions. For instance, if a camera system records that the vehicle is beginning to wander outside the traffic lane, adaptive steering can automatically realign the car to the middle of the lane. Adaptive and stop and go cruise control, integrating steering and throttle control with the radar systems, can help to ensure that a car remains a safe distance from other vehicles or stationary hazards.

The car that controls itself, leaving the driver as just another passenger, is not our goal today — collision avoidance is. But even before that, new developments may be able to do enough, through such systems as brake assist and vehicle stability control, to minimize the effect of an oncoming accident. Our purpose is to help the industry bring more autonomy to safety systems so the driving experience is safer and more pleasurable for driver and passengers alike.

References

  1. European Parliament News, Ref. 20050928IPR00829.

  2. Insurance Institute for Highway Safety Status Report. Vol. 40, No. 1, Jan. 3, 2005.



ABOUT THE AUTHOR

Paul Grimme is senior vice president and general manager of the Transportation & Standard Products Group at Freescale Semiconductor.

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