6 ms·

So if you operate a bicycle you might understand what's actually going on here a bit more. The first parts of the movement are actually quite responsive but do

So if you operate a bicycle you might understand what's actually going on here a bit more. The first parts of the movement are actually quite responsive but don't result in a huge change. If the wheels moved as the drive dictated the car would flip over. You can't just magically make all the forward momentum go lateral without relying on road and tire friction to get the job done. This can hit limits / you just end up skidding the tires and going ass over end instead of turning because you yanked the wheels too dramatically. It would be like riding a bicycle and then turning the handlebars completely to one side while going at a good pace forward. You could argue why isn't the car just doing it because they're at a standstill and it should be safe to do so? It's probably a sane default in case there are no sensors / no velocity reading / etc.

hef19898 3y ago
A cybertruck can put the front wheels in a 90° angle? What is this, a professional drift car? By the way, if this is true, it is beyond stupid...
sonofhans 3y ago
> If the wheels moved as the drive dictated the car would flip over. Do you mean “… at high speed?” To me, it looks like the person just wants this car to steer the way literally every other car does. Your bicycle analogy — yes, that’s how they work, so pretty quickly you learn how to do that.
mutatio 3y ago
Satirical post I assume? The demo shows the person stearing couldn't apply urgency in directing the wheel, sounds dangerous. Onus should be on the driver being capable of making the steering angle appropriate for the conditions, defending eventually consistent steering is comical, now drivers must account for where and by what speed the wheel angle reaches the desired position?
- itishappy 3y ago
  > defending eventually consistent steering is comical That's how things work though. Momentum and material strain mean that nothing reacts instantly, and that changes with your speed, steering angle, and rate of change in speed and steering angle. So yes, all drivers must account for the where and by what speed the wheel angle reaches the desired position.
  - mutatio 3y ago
    I'd honestly class that as reductio ad absurdum, quantum mechanics dictates it is a probability my car might spontaneous become a pink elephant. I'm all for evidence showing the latency shown on the video is comparable to competing implementations, but I'm not interested in lazy arguments that all momentum is eventually consistent as a defence.
    - itishappy 3y ago
      > I'm all for evidence showing the latency shown on the video is comparable to competing implementations... It's a vehicle you can buy right now, and this clip comes from a review (thanks rainbowzootsuit). https://www.youtube.com/watch?v=TeqE1kOO3dE&t=709s https://www.youtube.com/watch?v=TeqE1kOO3dE&t=709s
throwanem 3y ago
> You could argue why isn't the car just doing it because they're at a standstill and it should be safe to do so? It's probably a sane default in case there are no sensors / no velocity reading / etc. So the argument is that even with critical sensors offline or not providing meaningful data, the automation should continue to operate as normal? I believe Boeing has said much the same. The outcomes they've had by it lead me to doubt the merit of the argument.
zettabomb 3y ago
The wheels move exactly as the driver wants in any vehicle with a mechanical steering rack. It's not a problem. Lag due to poor drive-by-wire implementation however is most definitely a problem and not a small one, it's a significant safety hazard.
- smallmancontrov 3y ago
  > The wheels move exactly as the driver wants If I try to turn the front wheel of my bike too far left or right it does not let me. Further, this is accomplished by a rubber bumper that continues to push for a short time after I let up, but it would be absurd to call this "lag." Normal operation of the bicycle never gets close to those limits. The question is whether this video is showing typical system lag -- in which case, yeah, I agree, it's a problem -- or whether it is showing limiting behavior in which case getting upset about it makes as much sense as getting upset over the rubber bumpers on my bike.
  - throwaway81348 3y ago
    I am not upset by a bike behavior because I know exactly what my wheels are doing just by holding the bars. Same in a mechanical steering rack. This here seems more like a guessing game
  - zettabomb 3y ago
    >If I try to turn the front wheel of my bike too far left or right it does not let me. Not sure what you're referring to here - I've got multiple bicycles and the headset bearing allows them to spin around 360 degrees, the only thing preventing them from going further is the cables and hydraulic hoses. >Further, this is accomplished by a rubber bumper that continues to push for a short time after I let up What bumper do you mean? Your handlebars, stem, and fork should be moving as a solid unit, with minimal deformation under any reasonable conditions. There's very little elasticity in the system, perhaps the biggest source is just the spokes (or the grips if they're quite thick). The behavior exhibited in the video is way more than any properly operating bicycle.
    - 3y ago
lloeki 3y ago
> The first parts of the movement are actually quite responsive but don't result in a huge change. > If the wheels moved as the drive dictated the car would flip over. Non drive by wire cars react instantly by virtue of having wheels and steering physically linked. One can tip over such a car in the same way as you describe, the only thing preventing it is a) physics which makes it a bit harder to apply enough force and b) physics which gives the driver feedback that they're doing it wrong. Which leads us to the crux of the issue here: this DBW implementation decouples the steering device not just physically in action but in dynamics and feedback as well: It's literally a joystick masqueraded as a steering wheel, with apparently little to no force feedback, and very obviously force feedback completely decorrelated from the actual angle of the wheels. Taking a side road through the bicycle example: one doesn't turn a bicycle by turning the handlebar, one turns a bicycle by angling the whole apparatus, and the front end follows due to its geometry. The same principle applies to a car's front suspension: the geometry of it makes it resist being turned, which provides quintessential feedback to safe operation. Without this, a critically important signal is removed. A second one is removed as there is jo way to know how angled wheels are relative to the car's body. Throw in latency into the mix and you get a surefire way to create an overcorrection feedback loop and be completely unable to react in even slightly non-ideal situations. This means that for any sort of safety that should be by design of the chassis and suspension the vehicle relies entirely on ESP, when ESP should be a last resort fallback when the normal mode of operation fails. Instead there is no fallback nor redundancy and ESP MUST work or this vehicle becomes a death machine at the slightest sideway skid that would be perfectly manageable otherwise, even without ESP. > sane default This means the vehicle changes its dynamic reaction to driver input. Training aircraft pilots about normal law vs alt law is already quite something, I don't think training drivers about similar things is going to be very successful.
- orwin 3y ago
  Would it be possible to force the front wheels to turn fast enough when the truck reaches high speed to cause an accident? That's a bit morbid, but if you can hack the computer or manipulate sensor input to change the car comportement, it'll be easier, more effective and more stealthy for assassination.

hef19898 3y ago

A cybertruck can put the front wheels in a 90° angle? What is this, a professional drift car? By the way, if this is true, it is beyond stupid...

sonofhans 3y ago

> If the wheels moved as the drive dictated the car would flip over. Do you mean “… at high speed?” To me, it looks like the person just wants this car to steer the way literally every other car does. Your bicycle analogy — yes, that’s how they work, so pretty quickly you learn how to do that.

mutatio 3y ago

Satirical post I assume? The demo shows the person stearing couldn't apply urgency in directing the wheel, sounds dangerous. Onus should be on the driver being capable of making the steering angle appropriate for the conditions, defending eventually consistent steering is comical, now drivers must account for where and by what speed the wheel angle reaches the desired position?

itishappy 3y ago
> defending eventually consistent steering is comical That's how things work though. Momentum and material strain mean that nothing reacts instantly, and that changes with your speed, steering angle, and rate of change in speed and steering angle. So yes, all drivers must account for the where and by what speed the wheel angle reaches the desired position.
- mutatio 3y ago
  I'd honestly class that as reductio ad absurdum, quantum mechanics dictates it is a probability my car might spontaneous become a pink elephant. I'm all for evidence showing the latency shown on the video is comparable to competing implementations, but I'm not interested in lazy arguments that all momentum is eventually consistent as a defence.
  - itishappy 3y ago
    > I'm all for evidence showing the latency shown on the video is comparable to competing implementations... It's a vehicle you can buy right now, and this clip comes from a review (thanks rainbowzootsuit). https://www.youtube.com/watch?v=TeqE1kOO3dE&t=709s https://www.youtube.com/watch?v=TeqE1kOO3dE&t=709s

throwanem 3y ago

> You could argue why isn't the car just doing it because they're at a standstill and it should be safe to do so? It's probably a sane default in case there are no sensors / no velocity reading / etc. So the argument is that even with critical sensors offline or not providing meaningful data, the automation should continue to operate as normal? I believe Boeing has said much the same. The outcomes they've had by it lead me to doubt the merit of the argument.

zettabomb 3y ago

The wheels move exactly as the driver wants in any vehicle with a mechanical steering rack. It's not a problem. Lag due to poor drive-by-wire implementation however is most definitely a problem and not a small one, it's a significant safety hazard.

smallmancontrov 3y ago
> The wheels move exactly as the driver wants If I try to turn the front wheel of my bike too far left or right it does not let me. Further, this is accomplished by a rubber bumper that continues to push for a short time after I let up, but it would be absurd to call this "lag." Normal operation of the bicycle never gets close to those limits. The question is whether this video is showing typical system lag -- in which case, yeah, I agree, it's a problem -- or whether it is showing limiting behavior in which case getting upset about it makes as much sense as getting upset over the rubber bumpers on my bike.
- throwaway81348 3y ago
  I am not upset by a bike behavior because I know exactly what my wheels are doing just by holding the bars. Same in a mechanical steering rack. This here seems more like a guessing game
- zettabomb 3y ago
  >If I try to turn the front wheel of my bike too far left or right it does not let me. Not sure what you're referring to here - I've got multiple bicycles and the headset bearing allows them to spin around 360 degrees, the only thing preventing them from going further is the cables and hydraulic hoses. >Further, this is accomplished by a rubber bumper that continues to push for a short time after I let up What bumper do you mean? Your handlebars, stem, and fork should be moving as a solid unit, with minimal deformation under any reasonable conditions. There's very little elasticity in the system, perhaps the biggest source is just the spokes (or the grips if they're quite thick). The behavior exhibited in the video is way more than any properly operating bicycle.
  - 3y ago

lloeki 3y ago

> The first parts of the movement are actually quite responsive but don't result in a huge change. > If the wheels moved as the drive dictated the car would flip over. Non drive by wire cars react instantly by virtue of having wheels and steering physically linked. One can tip over such a car in the same way as you describe, the only thing preventing it is a) physics which makes it a bit harder to apply enough force and b) physics which gives the driver feedback that they're doing it wrong. Which leads us to the crux of the issue here: this DBW implementation decouples the steering device not just physically in action but in dynamics and feedback as well: It's literally a joystick masqueraded as a steering wheel, with apparently little to no force feedback, and very obviously force feedback completely decorrelated from the actual angle of the wheels. Taking a side road through the bicycle example: one doesn't turn a bicycle by turning the handlebar, one turns a bicycle by angling the whole apparatus, and the front end follows due to its geometry. The same principle applies to a car's front suspension: the geometry of it makes it resist being turned, which provides quintessential feedback to safe operation. Without this, a critically important signal is removed. A second one is removed as there is jo way to know how angled wheels are relative to the car's body. Throw in latency into the mix and you get a surefire way to create an overcorrection feedback loop and be completely unable to react in even slightly non-ideal situations. This means that for any sort of safety that should be by design of the chassis and suspension the vehicle relies entirely on ESP, when ESP should be a last resort fallback when the normal mode of operation fails. Instead there is no fallback nor redundancy and ESP MUST work or this vehicle becomes a death machine at the slightest sideway skid that would be perfectly manageable otherwise, even without ESP. > sane default This means the vehicle changes its dynamic reaction to driver input. Training aircraft pilots about normal law vs alt law is already quite something, I don't think training drivers about similar things is going to be very successful.

orwin 3y ago
Would it be possible to force the front wheels to turn fast enough when the truck reaches high speed to cause an accident? That's a bit morbid, but if you can hack the computer or manipulate sensor input to change the car comportement, it'll be easier, more effective and more stealthy for assassination.