Collision avoidance has long been important in video games, and it’s now starting to appear in real life. High-end vehicles include a number of collision avoidance technologies that are rapidly becoming mainstream. If your current car doesn’t have them, it’s a good bet that your next car will.
Before collision avoidance technologies can help you avoid collisions, your car first has to be computerized; with as many as 100 processors in a mid-range car, that’s a done deal. The first electronic control units (ECUs) in passenger vehicles date back to 1971 when Ford introduced a 4-sensor, 3-channel anti-lock braking (ABS) systems in the Lincoln Continental. By quickly and repeatedly braking to the skid point ABS systems can reduce stopping distance by 30% compared to what a skilled driver could hope to accomplish.
Even with ABS assistance if you brake hard on a rain slick street your car can careen out of control. Electronic Stability Control (ESC) systems can detect both skidding and loss of steering control. They detect when the car is going in a different direction from where you’re steering it, then they apply braking selectively to individual wheels to keep the car on an even keel; some units may even throttle back the engine until you regain control. If a crash seems immanent the ESC system will pre-tension seatbelts. All new vehicles sold in the U.S. since 2012 have electronic stability control.
On the Radar
ABS and ESC systems help you out once a collision is imminent, but how can you foresee and forestall a probable collision? By the use of radar-based adaptive cruise control (ACC). When the radar detects a possible collision it first gives an audible warning to the driver as well as a visual signal projected onto the windshield. If the warnings aren’t heeded the ACC will initiate braking—and, if necessary, steering—in order to avoid the collision.
In the early 1970s automobile manufacturers began experimenting with millimeter-wave radar for collision avoidance, though the suitcase-size devices were hardly practical for the family car. Modern systems employ both long-range radar (LRR) operating at 77 GHz and short range radar (SRR) operating in the 24-26 GHz range.
Long-range radar is typically used to look far ahead for possible obstacles on which you’re closing; they require your attention but not immediate action. Short-range radar is better suited for crowded, urban environments. SRR can be used for blind-spot detection (BSD), raising a lane change warning (LCW) if you start to change lanes when a car is approaching from the rear. If you don’t react quickly to the warning the ESC system can prevent you from steering into that lane. Narrow-band SRR systems operating in the 21.65-26.65 GHz ISM band may use multiple antennas for beam forming, enabling them to narrow their focus to a particular approaching vehicle while ignoring nearby traffic.
Camera sensors are sometimes used in conjunction with radar in ACC systems. Backup cameras have proven their worth for city parking and just backing down your driveway. Side mounted cameras can serve as blind-spot detectors and warn of pending dangers to the side while the radars focus on the line of travel. Infrared night-vision cameras can detect pedestrians or animals in the road ahead that radar may discern but not be able to identify; using the windshield like a heads-up display the road ahead is much more comprehensible than what your headlights show on a dark night. The results from radar and camera sensors are fused with vehicle acceleration, braking, and handling systems to reduce the possibility of accidents.
Hardware Makes It Happen
One thing that all collision avoidance technologies require is low latency data processing and rapid response to pending problems. A car traveling at 70 miles per hour covers 100 feet in less than a second; a distracted driver who suddenly became aware of an obstruction in the road could easily travel the length of a football field before even applying the brakes. A radar equipped adaptive cruise control system, detecting the problem as well as the driver’s hesitation, could respond in a fraction of a second by applying the brakes and, if necessary, steering around the obstruction. Every step in this process – from detection to correction – requires a fast, flexible computing platform.
The Intel® Atom™ processor has been widely adopted in transportation applications, thanks to its speed, flexibility, low power consumption, and ability to operate in demanding environments. The dual core Intel Atom processor D2550 (formerly Cedar Trail) doubles down on these capabilities. Running at 1.86 GHz the D2550 has a memory bandwidth of 6.4 GB/s and an integrated graphics processor. Intel® Hyper-Threading Technology delivers two processing threads to each physical core, enabling highly threaded applications to get more work done in parallel, completing tasks sooner. The D2550’s Intel® 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory. In short the Intel Atom processor D2550 is particularly well suited to the applications described above.
Figure 1. Intel® AtomTM processor
D2000/N2000 series system block diagram
The new MS-9896 Fanless 3.5” Embedded Board from Micro Star International (MSI) is a small form factor single board computer (SBC) built around the Intel Atom processor D2550/N2800/N2600 Dual Core CPU, an Intel® GMA3650 Graphics Controller, and an Intel® NM10 Express chipset. Designed to work from a 12V supply the MS-9896 supports DDR3 1066 MHz SO-DIMM memory up to 4 GB and can drive two independent displays (VGA/HDMI/LVDS). The numerous I/O channels include 6x USB 2.0, 4x COM, 8-bit GPIO, 2x GbE LAN, and 2x PCIe.
The COM-CV Rev.B-Com Express CPU Module from Aaeon Technology is a compact COM Express Type 2 SBC. It includes a 1.86 GHz Intel® Atom™ D2550, 1.6 GHz Intel Atom processor N2600, 1.86 GHz Intel Atom processor N2800 (optional), 4 GB of DDR3 memory, 8x USB2.0, GPIO 8-bit, 3x PCI-Express, 2x 32-bit PCI00, and 1x Gigabit Ethernet. An 18/24-bit dual channel LVDS interface can support a screen resolution of 1366 x 768 pixels. The COM-CV unit can operate from 32-1400F (-40-800C) at up to 90% relative humidity.
As radar-based collision avoidance systems become more capable, the era of completely autonomous vehicles is getting closer. Adaptive cruise control systems—interacting with other vehicles and intelligent highway infrastructure—will interact smoothly with drivers, greatly reducing the frequency and seriousness of accidents.
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