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Hypothetical: What happens if you blow a tire on Autopilot?

Discussion in 'Model S' started by Todd Burch, Jun 5, 2016.

  1. Todd Burch

    Todd Burch Electron Pilot

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    So you're driving down the highway at 70mph on autopilot and you blow a tire.

    What happens?

    My guess is that when autopilot is engaged it always has a positional target for the car, and if a tire blows it will apply steering to attempt to maintain position in the lane (just like when countering strong crosswinds). However, I think autopilot also has an enforced maximum turning angle for a given speed, and this could easily be exceeded in this scenario.

    Hopefully the car would recognize a rapid loss in pressure in one of the tires and begin slowing.

    Anyone had this happen, or have theories on how it behaves?
     
  2. chillaban

    chillaban Member

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    A flat tire TPMS fault or ESP engagement should immediately disconnect autopilot and give you the red "OMG TAKE OVER NOW" beeps. That's definitely how it works in my current Audi with TACC + LDW, as I've found the hard way.

    You'd be left with modern sports car ESP + ABS making an attempt to keep your car moving the way the steering wheel is pointed until you react. Much like what happens when you blow your tire in any $80k car.
     
  3. stopcrazypp

    stopcrazypp Well-Known Member

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    Like Chillaban, given the existence of the TPMS system, I would expect the autopilot system to disengage by default. If TPMS did not exist (or malfunctioned and didn't report a fault), then perhaps the scenario you described can happen.
     
  4. Saghost

    Saghost Active Member

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    I'm hoping it's smarter than that. Dropping AP abruptly when the tire blows out is a recipe for disaster - the driver may be distracted, may not have their hands on the wheel, etc. Those first couple seconds of the incident are probably the difference between a minor inconvenience and a major accident.

    My hope would be that since it has the TPMS and wheel speeds, AP knows exactly what happened, and throws the steering limits out the window - starts slowing as quickly as seems safe, steers as necessary to hold the lane (with help from stability control as needed,) and screams for help (red takeover now, possibly some sort of blowout warning) - but doesn't disengage until it feels the human take control of the steering.
     
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  5. stopcrazypp

    stopcrazypp Well-Known Member

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    Maybe there would be a buffer time before actual disengaging (as I believe it has today in other scenarios), but I would expect it to sound the alarm immediately.
     
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  6. Saghost

    Saghost Active Member

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    An immediate alarm makes sense. I'm just hoping AP keeps the car under control until the human is up to speed and understands what they need to do...
     
  7. kort677

    kort677 Active Member

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    It really shouldn't be any more dramatic than have a blowout in any other car. while using the AP you are obliged to take over immediately in the event of any abnormal occurrence. you should not be distracted, like reading text, grabbing your girlfriend or reading a book. like having a blowout while driving any other car you would strive to maintain control of the vehicle and bring to a stop in a controlled safe manner. thinking AP will effectively bail you out is not only beyond the capabilities of the AP system it is just foolish.
     
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  8. chillaban

    chillaban Member

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    Autopilot isn't magic, guys.... There's a reason why the manual says you need to be prepared to immediately take over at any moment. The best outcome you can expect is that Autopilot will immediately disengage and sound an alarm to get your attention.
     
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  9. TaoJones

    TaoJones Beyond Driven

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    This would be an excellent scenario/question to forward to Tesla through, for example, the Tesla owners club ombudsman/dedicated Tesla resource.

    Let us know what they say :).
     
  10. Saghost

    Saghost Active Member

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    I tend to think Autopilot pretty much is magic - at least under Arthur Clarke's definition. :)

    Certainly in this situation intelligent programming has a much better chance of keeping control in the critical first second or two than a human does - the car knows in milliseconds that there was a blowout, and which tire blew.

    I don't see any reason the computer can't be programmed to handle the initial moments of the blowout better than a human who was actively driving at the moment of blowout can, let alone one who is disengaged or distracted.
     
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  11. stopcrazypp

    stopcrazypp Well-Known Member

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    I think is his point is that although it can be, but don't expect it to be.
     
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  12. ecarfan

    ecarfan Well-Known Member

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    The driver -- that means you, human! -- takes control of the car within one second and safely slows to a stop.

    Which is what people have been attempting to do since the first cars with pneumatic tires hit the roads.

    During that first second after the tire fails, AP will of course attempt to continue safely steering the car.

    This is a non-issue.
     
  13. PDFS

    PDFS PDF's tesla

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    In a previous thread where I am op. I described a blowout the thread was "blowout tire on the interstate". I was using autopilot. Thought I was paying attention and did not see anything on road prior to blowout. I heard two loud pops sounded like gun shots. I grabbed the wheel immediately so I can not tell you if AP turned off or attempted correction immediately a warning signal Came on stating low air pressure. I stayed in center lane for less than a minute and then pulled off highway. I know it was not a gun shot as I had a 2 to 3 inch scratch on panel behind the tire and slight dent in the scratch. The hole was in the sidewall about the diameter of the tip of my little finger.
    From the time I heard the pop to the time I took control was at most seconds if not less than a second. Traffic was medium to heavy.

    I am working with admin to change my user name
     
  14. Todd Burch

    Todd Burch Electron Pilot

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    Unfortunately most of this thread for some reason has descended into "you're responsible, you're still the driver!" and "Autopilot is not autonomous driving!" comments.

    Yes, I know all that. I'm asking out of curiosity about how the system responds--not how I should respond (which of course is to take over immediately).

    Guess I should have made that clear in the original post.
     
  15. PDFS

    PDFS PDF's tesla

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    When my tire blew out I know the car stayed centered in my lane until I took over. The length of time I cannot estimate because it happened so fast. From the time I heard the pop I can tell you I scanned the front to see if it was something in front of me looked left and right then in rear view mirror. Then I felt that thump thump thump feeling of driving on a flat at 60 to 70 mph. Was it a second before I took over? Longer or shorter I can not say. I do know the car never swerved. It happened so fast I cannot say how long or far ap stayed in control before I took over

    I am not trying to make a statement about driver responsibility. From my experience I just can't say how ap reacted. It would be great if tesla could look at the vehicle record at the time and let us know. As soon as I pulled onto the shoulder I called roadside assistance. You would think this was great data for future development of ap

    At the time I was more broken hearted over the scratch on a car less than a week old and also worried about being rearended on the shoulder while waiting for tow truck
     
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  16. Todd Burch

    Todd Burch Electron Pilot

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    So it sounds from your experience that the autosteering was reacting just as it would if there were a strong crosswind--applying corrections to try to maintain the lane--which is what I would expect.
     
  17. Vitold

    Vitold Member

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    I think AP would disengage if there was steep deviation between steering input and direction vector as with front tire blowout. Otherwise, (probably mostly with rear tire blowouts) it would try to compensate.
     
  18. PDFS

    PDFS PDF's tesla

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    My blowout was the rear passenger tire
     

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