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DRCC inputs

Discussion in 'Gen 3 Prius Technical Discussion' started by macman408, Sep 27, 2010.

  1. macman408

    macman408 Electron Guidance Counselor

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    So being the geek that I am, I sometimes think about how I might implement a DRCC/PCS system, and wonder how the actual implementation is done. For example, it has to know whether the car in front of you is in the same lane or a different one, or an oncoming lane. Does it get input from the steering wheel to know how sharp of a curve you're in? Or perhaps it uses the LKA system as well (though obviously that could only be advisory, since it can't always find the lane)? And it can't get confused by parked cars or other stopped obstacles (unless you're actually going to hit them), so does it filter out things that are moving at 0 mph until you're too close to avoid them?

    Does anybody here actually know what all they use for inputs to their algorithms? They work impressively well; if only the LKA and APGS were so thoroughly polished... They're quite good, but not nearly as perfect as the DRCC seems to be.
     
  2. cproaudio

    cproaudio Speedlock Overrider

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    The radar is behind the Toyota badge above the front bumper. I guess it's pretty narrow radar beam because it will not detect cars in next lane. If the curve is sharp enough, it will have unintended braking or acceleration. The problem with LKA is not the camera. It's the lane markers. A lot of interstates in CA are poorly maintained. The state highways are better maintained. The LKA camera picks up reflectors, white and yellow paint strips, broken lines and solid lines. LKA needs lane markers on both sides to work. The problem is that when the budget is low, Caltran just reoil the cracks. The lane lines get run over with those oil and the lines become dull. Also sometimes Caltran had to detour the road so they had to strip the lane paint and use temporary reflector tapes as lanes. Sometimes they don't even use them and just use the cracks on the road as lane dividers. Sometimes they don't even bother stripping the lane paint and just reoil them. The LKA camera has hardtime picking up those lines. Therefore LKA is not as polished as DRC. LKA works fantastically if the road is brand new and the lane markers/dividers are freshly painted and the reflectors are newly installed.
     
  3. macman408

    macman408 Electron Guidance Counselor

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    I've always had the car do quite well at detecting the car in front of me, even in sharp turns.

    As for LKA, I say it's not as polished because even on a perfect road, it often loses sight of the lanes with a shadow from a tree or an overpass. And I have had it work quite well on two-lane roads with only center stripes and not outside stripes. Might depend on being able to see the edge of the pavement, perhaps; with a wide asphalt shoulder, it might not find the lane without a line on the right side.
     
  4. cproaudio

    cproaudio Speedlock Overrider

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    I've had unintended braking and acceleration due to sharp turns. The distance setting play some part on this. The farther distance setting, the higher chance of unintended braking and acceleration.
    shadows play a big part of LKA not able to detect the lanes. Night driving is perfect for LKA. I have never able to get the LKA to work on two-lane roads with only center stripes w/o outside lines. I don't use it that much anyway.
     
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    The sharpest curve I can think of is a decently sharp curve (~60° although it feels like 90°) at 80km/h. With a curve that sharp, it will pulse as it sees the car, then loses it, then sees it again. I noticed if I turn the wheel more, it has a better chance of seeing it (I don't know if it's b/c of steering angle or because the radar beam can detect the car in front because the angle btwn me and the car in front is narrower).


    That's the only time I've seen it pulse. Normal curves on highway (i.e. gentle ones) have no issues. No issues with an off ramp that curves with metal railings. I assume it filters out objects that are stationary (which may explain why some people wonder why DRCC doesn't detect cars stopped at a traffic light)