4 ms·

>Your rims might If they don't something is broken. >your tires don't. I did say "wheels", which generally speaking means the rim. Yes, I'm well aware of tir

>Your rims might If they don't something is broken. >your tires don't. I did say "wheels", which generally speaking means the rim. Yes, I'm well aware of tire deformation and contact patch mechanics, but that's not the issue here - the rims on the truck are not moving in sync with the wheel. It's just not acceptable.

itishappy 3y ago
> If they don't something is broken. The speed of sound in steel and roughly 1m of steering column put the theoretical minimum latency at 0.2ms. Manufacturing tolerances and material strain put minimum bounds on accuracy as well. Your entire suspension, down to the rigidity of the individual linkages, influences the steering of your vehicle. > Yes, I'm well aware of tire deformation and contact patch mechanics, but that's not the issue here... I think it's very relevant to know that cars already take the direction of the tires/rims/wheel as more of a suggestion. The "tightness" of the steering and the suspension varies drastically between vehicles. So what is the issue here? How it drives. I don't have one, but a common comment I've found in reviews is that it's "too sensitive." I think this is an imagined problem.
- lloeki 3y ago
  > The "tightness" of the steering and the suspension varies drastically between vehicles I could push your argument forward a bit more: the same vehicle can have tightness change as speeds goes up: electric power assistance progressively reduces as speed goes up. Why? because electric power steering is so powerful that it would be too easy to quickly turn wheels at speed. So the helper reduces, making it harder to turn the wheel in the same way that it became harder before power steering because physics. I needs more force, but the lag doesn't change, and neither is the gear reduction ratio, nor the absolute angle of the steering wheel to the actual angle of the wheels relative to the body. > I think it's very relevant to know that cars already take the direction of the tires/rims/wheel as more of a suggestion. I see this vehicle as introducing a fundamental breaking change in how automobiles are being operated: a) previously: you the driver physically control the car parts. You drive, operating the car by transforming high level intent to low level commands. You're the pilot sitting at the helm and your job is made easier with some helpful systems (ABS, ESP, cruise control, automated transmission, lane assist, what have you) that you can shunt. b) this vehicle: you communicate intention "I want to go in this general direction" / "Set a course to Rigel VII. Maximum warp" and someone else follows your instruction and drives the car for you. The physics is abstracted away. You're not the pilot, you're the captain, and captains don't go to helm. Up til now we've seen a) being progressively automated, working up towards full automation. This vehicle instead appears to be designed to be designed downwards from full automation, offering a degraded mode of operation from full automation that looks like a) but is fundamentally different from a). You can't shunt systems because that would prevent the actual pilot from operating the vehicle. In fact the pilot could very well do things that would be surprising and you would not be able to override it because your role is higher up. I fully expect this design to lead to the cap'n turning the wheel slightly left but the pilot "refuses" to comply and slaloms around a bunch of pedestrians.
- zettabomb 3y ago
  You're correct that nothing can move instantaneously, at a maximum it's bounded by the speed of sound in the material. But can you detect a 0.2ms delay? Probably no human can. What about a 2ms delay? Potentially some people can. What about a 20ms delay? Probably, although it's still very small. Perhaps saying that the wheels move "exactly" as the driver intends in a rack and pinion system is too absolute, but if you can't see or feel this delay then I'd argue that to the human driving it's irrelevant. You can see the lag in the video, which admittedly is slowed down, but if we assume the original frame rate was 60fps then there's a minimum of a 16.7ms lag and I'd estimate it's at least 3-4 frames so more like 50.0-66.7ms, which is absolutely noticeable. Why should we accept performance which is clearly worse than a mechanical system? This is a delay that exists on top of all the other factors you've mentioned, not in lieu of them. It casts doubts on the functional safety of the system.

itishappy 3y ago

> If they don't something is broken. The speed of sound in steel and roughly 1m of steering column put the theoretical minimum latency at 0.2ms. Manufacturing tolerances and material strain put minimum bounds on accuracy as well. Your entire suspension, down to the rigidity of the individual linkages, influences the steering of your vehicle. > Yes, I'm well aware of tire deformation and contact patch mechanics, but that's not the issue here... I think it's very relevant to know that cars already take the direction of the tires/rims/wheel as more of a suggestion. The "tightness" of the steering and the suspension varies drastically between vehicles. So what is the issue here? How it drives. I don't have one, but a common comment I've found in reviews is that it's "too sensitive." I think this is an imagined problem.

lloeki 3y ago
> The "tightness" of the steering and the suspension varies drastically between vehicles I could push your argument forward a bit more: the same vehicle can have tightness change as speeds goes up: electric power assistance progressively reduces as speed goes up. Why? because electric power steering is so powerful that it would be too easy to quickly turn wheels at speed. So the helper reduces, making it harder to turn the wheel in the same way that it became harder before power steering because physics. I needs more force, but the lag doesn't change, and neither is the gear reduction ratio, nor the absolute angle of the steering wheel to the actual angle of the wheels relative to the body. > I think it's very relevant to know that cars already take the direction of the tires/rims/wheel as more of a suggestion. I see this vehicle as introducing a fundamental breaking change in how automobiles are being operated: a) previously: you the driver physically control the car parts. You drive, operating the car by transforming high level intent to low level commands. You're the pilot sitting at the helm and your job is made easier with some helpful systems (ABS, ESP, cruise control, automated transmission, lane assist, what have you) that you can shunt. b) this vehicle: you communicate intention "I want to go in this general direction" / "Set a course to Rigel VII. Maximum warp" and someone else follows your instruction and drives the car for you. The physics is abstracted away. You're not the pilot, you're the captain, and captains don't go to helm. Up til now we've seen a) being progressively automated, working up towards full automation. This vehicle instead appears to be designed to be designed downwards from full automation, offering a degraded mode of operation from full automation that looks like a) but is fundamentally different from a). You can't shunt systems because that would prevent the actual pilot from operating the vehicle. In fact the pilot could very well do things that would be surprising and you would not be able to override it because your role is higher up. I fully expect this design to lead to the cap'n turning the wheel slightly left but the pilot "refuses" to comply and slaloms around a bunch of pedestrians.
zettabomb 3y ago
You're correct that nothing can move instantaneously, at a maximum it's bounded by the speed of sound in the material. But can you detect a 0.2ms delay? Probably no human can. What about a 2ms delay? Potentially some people can. What about a 20ms delay? Probably, although it's still very small. Perhaps saying that the wheels move "exactly" as the driver intends in a rack and pinion system is too absolute, but if you can't see or feel this delay then I'd argue that to the human driving it's irrelevant. You can see the lag in the video, which admittedly is slowed down, but if we assume the original frame rate was 60fps then there's a minimum of a 16.7ms lag and I'd estimate it's at least 3-4 frames so more like 50.0-66.7ms, which is absolutely noticeable. Why should we accept performance which is clearly worse than a mechanical system? This is a delay that exists on top of all the other factors you've mentioned, not in lieu of them. It casts doubts on the functional safety of the system.