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Steer by wire

Discussion in 'Model 3' started by theboom1, Jun 6, 2016.

  1. theboom1

    theboom1 Member

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    With the first production car on the road using steer by wire, its got me thinking. I feel soon more companies will try this out. So far the one model has gotten bad reviews in any type of driving that not normal traffic driving due to the horrible feedback and it changing steering ratios mid turn. I know this is helping lead to easier autonomous driving but like me and some have discussed, many feel that the steering wheel will stay in the car so a driver can drive if they want to and be shadowed over by the computer so it can protect the driver and manage traffic flow when needed. With that being said, do you think that they will eventually be able to make a drive by wire system that can transmit back fast, accurate feedback to the driver that would help greatly in certain conditions and driving styles?
     
  2. JeffK

    JeffK Active Member

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    Anyone can do it now if they tried. If it's good enough for fighter pilots why not cars.
    The problem with the Infiniti version was two fold... first it would fail if the engine compartment was too cold and the backup system couldn't engage fast enough in an emergency. Poor engineering on their part doesn't mean it's impossible.
     
  3. Frank Schwab

    Frank Schwab Member

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    Oh, yeah, it'll come. Some company will do it "right" (meaning, the car enthusiast magazines like Road and Track will decide they prefer it to a wheel when testing at the track), and the floodgates will open.

    You can't think of the problem as a displacement problem. You'll never get good steering if moving the joystick 2" to the left is equivalent to turning the wheel half a turn. You can't think of it as a pressure problem, where the pressure you put on the stick determines how far the wheels turn. This is a problem that requires combining displacement, and pressure, and feedback, such that you get an instant feel for what the car is doing. I can imagine differing settings - the ultra-lux setting with little feedback (kind of like a 70's cadillac with overboosted power steering), and the ultra-sport with full feedback. And, as JeffK referred to fighter pilots, the research, design, and feedback you could get from them would be invaluable in getting this working right.

    But there's no technical barrier to having a great feeling drive-by-wire system. Personally, I want a sidestick so I can keep my arm on the armrest and drive with my wrist. It'll make it a bit harder to drive with a burger in one hand and a drink in the other, but I'll get over it.
     
  4. zenmaster

    zenmaster Member

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    Yes because everything you'd need to feel in your grasp to get a sense of that road and tire feedback could be simulated. I think manufacturers should do this, because it's good info for the driver. But I don't think it will be easy to do properly.
     
  5. FloridaJohn

    FloridaJohn Member

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    Laws will have to be changed first. I'm pretty sure there is a requirement for the steering wheel to be mechanically linked to the steering linkages. This was done so that steering will still work even if the "assist" part failed. Getting a joystick mechanically linked is not easy.
     
  6. Saghost

    Saghost Active Member

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    I think I agree with Jeff - the technology exists today, though it may not be cheap or easy.

    The biggest challenge is ensuring safe failure modes - and convincing people they are there.

    I'm inclined to say the logical place to start with that is a block of three voting computers on a UPS battery, and dual sensors/actuators.

    The dual actuators will be easy - most modern steering racks, including the Model S, are 'dual pinion' systems - meaning that the steering assist motor drives a separate pinion on the steering rack in the side of the car the steering wheel isn't on. Replace the steering column with a second drive motor, and you have a redundant steering system with either motor able to drive the rack in an emergency.

    Artificial force feedback well of course be necessary, but that opens some interesting possibilities of its own. If the car knows you're on the ragged edge of losing traction, it could insert a force detent in the feedback - it'll feel like a little edge you have to pull past to lose control. Pushing across lane lines could be handled the same way - and both could be enabled/disabled by software.
     
  7. theboom1

    theboom1 Member

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    Are you calling a steering wheel a joystick or are you talking about a real joystick? Because I don't see how you could have any useful feedback in a joystick.
     
  8. FloridaJohn

    FloridaJohn Member

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    I was using them interchangeably. Basically I was referring to the steering input user interface. If one was to go full steer-by-wire, then the steering input doesn't have to be a "wheel" anymore since it is just an electrical signal, so a joystick would work just as well. Force feedback in joysticks is already an actual "thing," so I don't think it would be that hard to do.

    Haptic technology - Wikipedia, the free encyclopedia

    But you still are required by law to have a physical link between the steering input and the steering mechanism, so a steer-by-wire system, although possible to do, is illegal at this point in time. This similar to how Tesla wanted to remove the side mirrors to improve aerodynamics, but couldn't due to the laws about car mirrors.
     
  9. JeffK

    JeffK Active Member

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    With autopilot your car can drive itself while you sit back and play with your joystick...:D
     
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  10. Dan Detweiler

    Dan Detweiler Member

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    Gross!

    ...oh wait...
     
  11. theboom1

    theboom1 Member

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    One thing on this. How well could you control a car with joystick? I recently read a post on a forum that offered a way for the sports car and the people who like to drive them to live on in a world of autonomous cars. It said the car would actually be driving(so you get all the benefits of the car self driving) but you could have a joystick in the middle. If cars are automous then the speed limit of the vehicle could be simply the capability of they vehicle(so high for sports cars). Puck the joystick forward to speed up, pull it back to activate the brakes and slow down, push it right and left to tell it to change lanes and really far to the left or right to make a turn. Obviously none of the inputs will do anything if the car doesn't think its a good idea(aka cause a crash). This could also be a way to drive the car at slow speeds like you driveway or parking lot.

    This got me thinking. How precise can you input in two inputs, forward-back, side-to-side, using a joystick? I know planes do it but you don't have to be as exact. Maybe have two separate joysticks, one for throttle and turning? Or maybe it can only move side to side for steering and you twist it like a motorcycle for the throttle? The steering would be ultra adaptive depending on your speed. It was said in this thread that it could provide feedback from the front tires so that is covered. Another thing is how well could it do if you are tracking it where you are 100% controlling it and not just half way controlling it by just telling it what to do. Full speed track driving with a joystick? How would that go?

    If we can get all of this down we could free it up so we can use it fully while driving on the road if we want(actually controlling it, not just telling it what to do). Still with the computer approving every move we do of course.
     
  12. BluestarE3

    BluestarE3 Active Member

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    Note to self: Another reason not to rent out/car share my future Model 3.
     
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  13. Mark C

    Mark C Member

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    Steer by wire (sbw) does not automatically mean an F-16 style joystick in your left hand while you are going down the road. Video consoles have optional (?) steering wheels for some of their games. No doubt, a manufacturer trying this sbw concept would use a traditional looking steering wheel since it's so familiar to everyone who has ever driven a car. However, IMHO, the wheel wouldn't need to move more than a half rotation either direction, if it increased the amount of turn in a progressive, linear fashion. You'd probably still need a short drivers training course before jumping out into traffic though.
     
  14. JeffK

    JeffK Active Member

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    Much of the problem with steer by wire is that you'd need to put motors in the system to offer feedback to the driver in addition to redundant hardware in case of failure.
     
  15. dsvick

    dsvick Member

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    I think that's illegal too, unless you have very heavily tinted windows.
     
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  16. McRat

    McRat Active Member

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    #16 McRat, Aug 24, 2016
    Last edited: Aug 24, 2016
    Say a steering wheel rotary encoder loses it's reference signal. Pretty common failure for rotary encoders, or linear for those JoyStick folk.

    Which way do you point a car going 45 mph if an impact or electric failure make the Zero mark illegible? -75°. -60°, -45°, -30°, 0°, etc.
    Now remember the 0° mark from the driver's request is actually unknown due to encoder failure.

    Why is 45mph significant? More than 90% of fatalities occur at less than 45.

    I imagine there will always be a physical link between the steering wheel and tires. However, the Electronic Warfare systems will allow overrides, corrections, enhanced feedback. Sort of like your brake and throttle today. Oh, and steering on modern cars. Cars have electric assist today, not hyd. I think they switched about 5 years ago for passenger cars.

    My 2002 Low Brow Chebby will correct steering mistakes at 150mph quick enough to avoid the barriers. It works great on snap oversteer when somebody cuts into your line. (I had to submit a doctored IQ report to buy a Chebby, divorce my sister, and show up in clothes that weren't Real Tree camo before they would allow the purchase).
    The 2010 I beat on will even allow some tasty drifting when in NORMAL model, even in the rain.

    However, the steering and brakes always have a mech link. I can FORCE the car to go in any direction I want. I can torch all four tires in full ABS/PwrBrk failure mode. Just bend that middle pedal with your foot.

    That being said, today, for most mass produced cars, a driver with seat time will cut better laps than software will. The car cannot "see" eroded track, sand, marbles, oil, or remember that guy who drives badly you must correct for.
     
  17. theboom1

    theboom1 Member

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    Why do we need redundant hardware for steering but not a manual override in future self driving car in case of failure?
     
  18. JeffK

    JeffK Active Member

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    Who said there's no manual override? In every autonomous car to date and even the stuff Bosch and MobilEye are working on have a manual override.

    There are also redundancies in the autonomous hardware.
     
  19. Garlan Garner

    Garlan Garner Active Member

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    This poor planet.

    Have we reached the point in society where steering is just to strenuous a task while driving?

    Lets go back into the old days. Tesla should create a model with "NO" power steering at all and make it a 6 month requirement to have one of these before you get your real car.
     
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  20. dsvick

    dsvick Member

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    I, for one, do not want steering by joystick or dial or touch pad - I've seen what happens when I play Forza on the XBox and it isn't pretty.
     
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