5 ms·

>Software would replace the sensors. This is a fault in design philosophy. Remember MCAS, where Boeing decided their solution to a hardware design problem was

by bumby 4y ago

>Software would replace the sensors. This is a fault in design philosophy. Remember MCAS, where Boeing decided their solution to a hardware design problem was a software workaround? I know it's tempting, but these types of design decisions need a very careful thought process to work; they shouldn't be a last-ditch workaround. I guess I give TSLA some slack here because it's only applied to parking, but I hope they don't apply the same design philosophy on more safety critical systems.

m463 4y ago
I think there are some parking scenarios that might be catastrophic. "backing into the pedestrian" is pretty bad, but what about fire hydrants or gas pumps?
- deleted 4y ago
  [deleted]
- jjoonathan 4y ago
  Those don't move, so memorizing their location/occupancy should work better.
  - Arrath 4y ago
    How much object persistence does this system actually have? Watching objects jitter around the screen and morph from a sign to a cone to a person back to a sign hasn't inspired confidence in me.
- doubled112 4y ago
  Aren't fire hydrant valves usually a few feet underground, which makes running them down not as exciting as it could be? Gas pumps (gasoline), at least in Canada, the pump is underground and you're really just holding a big nozzle. Bad, but not too bad. People have been driving into and through those for years. Natural gas lines and meters could be a catastrophe, but they're usually pretty close to a wall.
Xenoamorphous 4y ago
Therac 25 is another example of hardware being replaced by software and things goong terribly wrong.
diebeforei485 4y ago
MCAS wasn't to rectify a hardware electronics problem, it was for a dynamics/physics problem. The equivalent would be if, say, the car was designed to be overweight on one side and susceptible to tipovers, and had software to automatically turn the wheels the other direction when it felt like it.
- bumby 4y ago
  When I said hardware, I meant in the broader airframe hardware, not specifically electronics hardware. The physics you mention is a result of the center-of-gravity of the airframe design. The broader point being, it became cheaper and more expedient (at least superficially) to try and fix a hardware problem with software. (Although Boeing did also create a cringey option to incorporate already existing redundant AOA sensors only as software option, rather than as a default)
  - jaywalk 4y ago
    > The physics you mention is a result of the center-of-gravity of the airframe design. No, it's not. The larger size and more forward placement of the engines on the MAX caused it to pitch up in certain high angle-of-attack maneuvers, so MCAS was designed to automatically trim the aircraft to make it act more like the NG.
    - bumby 4y ago
      Yes, it is. But you don't have to take my word for it. >"heavier engines that are also cantilevered further forward on the wing to provide more ground clearance. That changes the center of gravity."[1] The "pitching up" is a direct result of the change in the center of gravity and thrust vector. [1] https://www.seattletimes.com/business/boeing-aerospace/faa-evaluates-a-potential-design-flaw-on-boeings-737-max-after-lion-air-crash/ https://www.seattletimes.com/business/boeing-aerospace/faa-e...
- lisper 4y ago
  > it was for a dynamics/physics problem Not exactly. The plane was (and still is) perfectly flyable without MCAS, but its handling characteristic were sufficiently different from the plane it was designed to replace that it required pilots to be retrained. That made its value proposition less attractive because of the extra training costs. MCAS was an attempt to make the new plane handle like the old one so pilots would not have to be retrained. And it failed catastrophically. The point is, it was a completely artificial problem produced by business considerations, not physics.
fegu 4y ago
They did the same with rain sensor a few years ago. Result: auto rain wipe is still in beta in 2023!
whalesalad 4y ago
Lol… they are going all in on cameras so yes it’s going to be used in critical safety systems. No more LiDAR. Relying entirely on computer vision without sensor fusion is asinine imho. https://www.forbes.com/sites/bradtempleton/2022/10/31/former-head-of-tesla-ai-explains-why-theyve-removed-sensors-others-differ/?sh=5103b4614ba8 https://www.forbes.com/sites/bradtempleton/2022/10/31/former...
- deleted 4y ago
  [deleted]
- judge2020 4y ago
  > No more LiDAR. Lidar is not in any cars. You're thinking about Radar, which they've added back with HW4. https://www.teslarati.com/tesla-hardware-4-hd-radar-first-look-photos/ https://www.teslarati.com/tesla-hardware-4-hd-radar-first-lo...
WalterBright 4y ago
> Remember MCAS, where Boeing decided their solution to a hardware design problem was a software workaround? The problem was the software wasn't dual path. There was nothing wrong with the concept.
- deleted 4y ago
  [deleted]
- bumby 4y ago
  Not the concept, the implementation. That's why I'm referring to it as a flaw in design philosophy. The did not follow through with the appropriate mitigations for using software in a safety-critical application.

by bumby 4y ago

m463 4y ago

I think there are some parking scenarios that might be catastrophic. "backing into the pedestrian" is pretty bad, but what about fire hydrants or gas pumps?

deleted 4y ago
[deleted]
jjoonathan 4y ago
Those don't move, so memorizing their location/occupancy should work better.
- Arrath 4y ago
  How much object persistence does this system actually have? Watching objects jitter around the screen and morph from a sign to a cone to a person back to a sign hasn't inspired confidence in me.
doubled112 4y ago
Aren't fire hydrant valves usually a few feet underground, which makes running them down not as exciting as it could be? Gas pumps (gasoline), at least in Canada, the pump is underground and you're really just holding a big nozzle. Bad, but not too bad. People have been driving into and through those for years. Natural gas lines and meters could be a catastrophe, but they're usually pretty close to a wall.

Xenoamorphous 4y ago

Therac 25 is another example of hardware being replaced by software and things goong terribly wrong.

diebeforei485 4y ago

MCAS wasn't to rectify a hardware electronics problem, it was for a dynamics/physics problem. The equivalent would be if, say, the car was designed to be overweight on one side and susceptible to tipovers, and had software to automatically turn the wheels the other direction when it felt like it.

bumby 4y ago
When I said hardware, I meant in the broader airframe hardware, not specifically electronics hardware. The physics you mention is a result of the center-of-gravity of the airframe design. The broader point being, it became cheaper and more expedient (at least superficially) to try and fix a hardware problem with software. (Although Boeing did also create a cringey option to incorporate already existing redundant AOA sensors only as software option, rather than as a default)
- jaywalk 4y ago
  > The physics you mention is a result of the center-of-gravity of the airframe design. No, it's not. The larger size and more forward placement of the engines on the MAX caused it to pitch up in certain high angle-of-attack maneuvers, so MCAS was designed to automatically trim the aircraft to make it act more like the NG.
  - bumby 4y ago
    Yes, it is. But you don't have to take my word for it. >"heavier engines that are also cantilevered further forward on the wing to provide more ground clearance. That changes the center of gravity."[1] The "pitching up" is a direct result of the change in the center of gravity and thrust vector. [1] https://www.seattletimes.com/business/boeing-aerospace/faa-evaluates-a-potential-design-flaw-on-boeings-737-max-after-lion-air-crash/ https://www.seattletimes.com/business/boeing-aerospace/faa-e...
lisper 4y ago
> it was for a dynamics/physics problem Not exactly. The plane was (and still is) perfectly flyable without MCAS, but its handling characteristic were sufficiently different from the plane it was designed to replace that it required pilots to be retrained. That made its value proposition less attractive because of the extra training costs. MCAS was an attempt to make the new plane handle like the old one so pilots would not have to be retrained. And it failed catastrophically. The point is, it was a completely artificial problem produced by business considerations, not physics.

fegu 4y ago

They did the same with rain sensor a few years ago. Result: auto rain wipe is still in beta in 2023!

whalesalad 4y ago

Lol… they are going all in on cameras so yes it’s going to be used in critical safety systems. No more LiDAR. Relying entirely on computer vision without sensor fusion is asinine imho. https://www.forbes.com/sites/bradtempleton/2022/10/31/former-head-of-tesla-ai-explains-why-theyve-removed-sensors-others-differ/?sh=5103b4614ba8 https://www.forbes.com/sites/bradtempleton/2022/10/31/former...

deleted 4y ago
[deleted]
judge2020 4y ago
> No more LiDAR. Lidar is not in any cars. You're thinking about Radar, which they've added back with HW4. https://www.teslarati.com/tesla-hardware-4-hd-radar-first-look-photos/ https://www.teslarati.com/tesla-hardware-4-hd-radar-first-lo...

WalterBright 4y ago

> Remember MCAS, where Boeing decided their solution to a hardware design problem was a software workaround? The problem was the software wasn't dual path. There was nothing wrong with the concept.

deleted 4y ago
[deleted]
bumby 4y ago
Not the concept, the implementation. That's why I'm referring to it as a flaw in design philosophy. The did not follow through with the appropriate mitigations for using software in a safety-critical application.