5 ms·
> 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 fl
by 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 agoWould 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.