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How does the self steering/lane assist work?

Discussion in 'Gen 5 Prius Technical Discussion' started by AgentPTFC, Aug 23, 2024 at 5:26 PM.

  1. AgentPTFC

    AgentPTFC New Member

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    Like the title states I'm just wondering how the system works, specifically how you tell it you're still paying attention. Some vehicles have a capacitive element in the steering wheel that only requires a hand to be touching the wheel to stay active. Some vehicles require you to periodically jiggle the wheel. Does the Prius use either of those systems or does it instead use the eye tracking camera to make sure you're paying attention and you don't need to touch the wheel at all?
     
  2. Trollbait

    Trollbait It's a D&D thing

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    Only the Primes with the TJA have the eye tracking cameras. That feature allows you be hands off. The other systems require hands on wheel, but I can't say exactly how the car determines that.
     
  3. Hammersmith

    Hammersmith Senior Member

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    Yes. lol

    In the regular Prius, you need to jiggle the steering wheel every 15sec.
    In the Prius Prime, using adaptive cruise control needs either the 15sec jiggle OR a hand on the steering wheel.
    In the Prius Prime in Traffic Jam Assist(<25mph), you can use no hands but need to have your eyes looking forward.

    Prius HEV only has a torque sensor in the steering column. The Prius Prime PHEV has the torque sensor, plus a capacitive sensor in the steering wheel, plus a pair of IR cameras on the steering column.
     
  4. AndersOne

    AndersOne Active Member

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    I was driving with both variants (torque vs capacitive) for a while and I have to say the capacitive sensors work very good (you barely have to touch it). I could get used to the torque too though.
     
  5. dbstoo

    dbstoo Senior Member

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    I like the capacitive system better. The torque system means that I have to frequently counter the car's chosen direction, and I found myself sometimes forcing the car to cross the lines that marked the lane boundaries.
     
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  6. Hammersmith

    Hammersmith Senior Member

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    Really? I use it extremely frequently(since it's the only system on my car) and I barely have to bump the wheel to silence the alert. It's such a small amount that other people in the car can't feel it. Are you overdoing it or is the Prime programmed differently than the HEV?
     
  7. dbstoo

    dbstoo Senior Member

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    I also used the torque system for proving that I was alert in my gen 4 Prius Prime Advanced. Twice a month I made 1000 mile round drip drives on the interstate. At the end of 10 hours of using it on the highway it's no longer relaxing to me.

    I've had much less frustration with the Gen 5 version.
     
  8. Hammersmith

    Hammersmith Senior Member

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    I'm planning to add the capacitive sensor to my HEV at some point, so I hope I'll be able to compare systems as well.


    I'm converting my black/silver/blue interior to the Prime's black/red/orange interior. One piece of that will be finding a red-stitched steering wheel from a Prime. I plan to get it from a wrecked Prime as soon as one appears in a salvage yard(if anyone knows of one, please please please let me know - none have shown up on Car-Part yet). I think it will come with the sensor and wiring for the capacitive touch, so I'll probably need to add a few wires from the steering wheel to the ECU and then see if the car recognizes the sensor like it did with my folding side mirror upgrade.
     
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  9. kenmce

    kenmce High Voltage Member

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    I will start by explaining that I don't have a 5th gen. Prius, I have another Toyota hybrid, so mine could be different.

    My Lane Keep Assist has a camera up by the top center of the windshield. It is specifically watching the fog line - the white line that runs along the right side of the road - and is is judging how close I get to that line. It can nudge the wheel left or right if it does not approve of my position.

    It can be fooled when an exit opens off to the right, and the line follows the exit. It can be mistaken about driveways, where there is no line. I leave mine turned off because it and I have different ideas about my position in the lane, and it is foolish to try and argue with a machine.
     
  10. Hammersmith

    Hammersmith Senior Member

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    If your current car is a 2016 Avalon like your sig says, then the system in the gen5 is definitely different(much more refined). You probably have TSS 2.0. The 2.0 system was tweaked a couple times(2.5 & 2.5+) before TSS 3.0 was released in 2023. I think the gen5 was the 4th model released with TSS 3.0(after the Crown, Corolla Hatchback, and bZ4X).
     
  11. AndersOne

    AndersOne Active Member

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    Actually, i realized that the capacitive steering wheel has torque detection as well. So its a superset and not an exclusive or.