General > General Technical Chat
Electric car for £9500?
SiliconWizard:
--- Quote from: Veteran68 on October 06, 2023, 02:05:31 am ---
--- Quote from: coppice on October 05, 2023, 05:46:30 pm ---If that was in adaptive cruise mode its normal, and has nothing to do with the regen vs hydraulic braking split. If you look at the manual for most ICE powered cars with adaptive cruise they say the automated braking will not apply more than 40% or 50% of total available braking. I haven't seen one that explains why. Around town, when the collision avoidance braking kicks in, that can be quite aggressive. A pigeon crossing quite close in front of my car one day produced very heavy braking, so the automated system is capable of an emergency stop, even though that one was spurious. Its a good thing nobody was close behind me.
--- End quote ---
My 2021 Audi Q5 will definitely slam on the brakes HARD if it thinks you're about to hit something. Like, snap you forward in your seatbelt and almost giving you whiplash. It's extremely unnverving when it's a false alarm and comes out of nowhere, where it misinterprets something as an imminent collision but it's not. You can disable it, but I do like the peace of mind that it brings if one day I'm not paying attention, fall asleep/pass out, or whatever. It might save somebody, and it's far faster than my reflexes could ever be -- I just wish their detection was a bit more foolproof.
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Yeah, that's not something I personally am comfortable enabling so far.
Simon:
the born/i3 screams blue murder when I am going around parked cars. when I drove an ioniq (uh horrible thing) it would scream at me when I approached a certain bend as it could not distinguish the pavement from the road and decided that I was headed for the school kids that it probably assumed where on the road.
These things will only work with good stereoscopic vision and god only knows how much processing power to do all of this in true 3D.
bd139:
I owned a model S for a couple of weeks (my father’s when he dropped dead). It was the same. Driving down the M4 at 70mph and it made the usual “phong” sound and tried to chuck me through the windscreen. Literally no other cars around. Even when it wasn’t trying to kill me it was complaining constantly.
If there’s no repeatability or determinism then you can’t trust the system. Hence I felt safer in my zero tech Citroen C3.
hans:
--- Quote from: Veteran68 on October 06, 2023, 02:05:31 am ---
--- Quote from: coppice on October 05, 2023, 05:46:30 pm ---If that was in adaptive cruise mode its normal, and has nothing to do with the regen vs hydraulic braking split. If you look at the manual for most ICE powered cars with adaptive cruise they say the automated braking will not apply more than 40% or 50% of total available braking. I haven't seen one that explains why. Around town, when the collision avoidance braking kicks in, that can be quite aggressive. A pigeon crossing quite close in front of my car one day produced very heavy braking, so the automated system is capable of an emergency stop, even though that one was spurious. Its a good thing nobody was close behind me.
--- End quote ---
My 2021 Audi Q5 will definitely slam on the brakes HARD if it thinks you're about to hit something. Like, snap you forward in your seatbelt and almost giving you whiplash. It's extremely unnverving when it's a false alarm and comes out of nowhere, where it misinterprets something as an imminent collision but it's not. You can disable it, but I do like the peace of mind that it brings if one day I'm not paying attention, fall asleep/pass out, or whatever. It might save somebody, and it's far faster than my reflexes could ever be -- I just wish their detection was a bit more foolproof.
--- End quote ---
Could be 2 different systems at play. Adaptive cruise is a comfort feature. Collision avoidance systems are safety features. It can make some sense that a comfort feature wont engage brakes at 100%, while a safety feature most definitely should.
Both systems also may use a different mix of sensors. IIRC collision avoidance systems almost always use some vision system, while ACC usually rely on some radar sensors as well. Radar sensors may have a non-zero min. range though, while vision may not work well at larger distances. There is probably some large amount of sensor fusion and data processing going on that is tuned "just so" (in next-gen they will call it AI powered for higher sales) in order to pass standard road tests. But practice may beg to differ.
I can understand keeping such a system on out of fear of driving into a truck or obstacle with >100km/h at night after a tiring day. But those unnecessary emergency stops are also not without danger, for example when someone is not expecting/reacting to it in time.
Correct me if I'm wrong, but iirc collision avoidance systems for pedestrian safety has been mandatory on all cars in EU for a few years now (even a VW Up! has it). But usually those baby-systems only work at low city speeds (30km/h max)
coppice:
--- Quote from: bd139 on October 07, 2023, 09:15:44 am ---I owned a model S for a couple of weeks (my father’s when he dropped dead). It was the same. Driving down the M4 at 70mph and it made the usual “phong” sound and tried to chuck me through the windscreen. Literally no other cars around. Even when it wasn’t trying to kill me it was complaining constantly.
If there’s no repeatability or determinism then you can’t trust the system. Hence I felt safer in my zero tech Citroen C3.
--- End quote ---
Most cars with a bunch of sensors are quite quirky. The ultrasonic sensors used for close in obstacle detection tend to alert once every trip or two on some low and innocuous kerb, or when a car creeps past in a jam, with an entirely reasonable separation from you. My car alerts about a frontal issue at the end of our drive. It drops about a metre from our house to the road with a gentle slope, but something about the relative position of the sloping car approaching the horizontal road triggers the ultrasonic sensors every time. That one is no bother. Its just expected now. Thankfully those sensors do behave well when you are relying on them in a tight car park.
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